The Foreign Secretary joined cross-party outrage at the timing and content of Mr Corbyn's first major speech as electioneering resumed after a truce to honour the victims of Monday's bombing of Manchester concert-goers.
Mr Johnson added that Mr Corbyn had "spent a political career sticking up for terrorists, sympathising with the IRA, with Hamas, with Hezbollah, and blocking every single piece of anti-terrorist legislation in the last 30 years.
Speaking to the BBC, the Foreign Secretary said: "Whatever we do, we can't follow the logic of the terrorists and start blaming ourselves or our society or our foreign policy.
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Whatever we do, we can't follow the logic of the terrorists and start blaming ourselves or our society or our foreign policy
"This has been caused not by us – as Jeremy Corbyn would have us believe – it's been caused by a sick ideology, a perverted version of Islam that hates us and hates our way of life.
"And to say anything now to legitimate or justify those who have carried out the atrocity in Manchester is in my view absolutely obscene and I think Mr Corbyn should be ashamed of himself."
Mr Corbyn repeatedly insisted that noone was to blame for atrocities but the terrorists and that foreign policy decisions could not "remotely excuse" violence like that committed by Manchester murderer Salman Abedi.
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But opponents accused him of playing into extremists' hands by suggesting the "war on terror" was a factor in heightening the threat and that Britain needed to take a "smarter" approach.
Addressing Labour supporters in London after a minutes' silence for the 22 dead and dozens wounded in Manchester, Mr Corbyn said that neither his patriotism nor his "determination to take whatever action is necessary to keep our country safe" should be doubted but "change" was needed.
Many experts had "pointed to the connections between wars our government has supported or fought in other countries, such as Libya, and terrorism here at home", he said.
"That assessment in no way reduces the guilt of those who attack our children.
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Opponents accused Mr Corbyn of playing into extremists' hands
"But an informed understanding of the causes of terrorism is an essential part of an effective response that … fights rather than fuels terrorism.
"Protecting this country requires us to be both strong against terrorism and strong against the causes of terrorism.
"The blame is with the terrorists but if we are to protect our people we must be honest about what threatens our security.
"We must be brave enough to admit the war on terror is not working."
Governments must minimise terrorists' chances by ensuring police were properly resourced, "that our foreign policy reduces rather than increases the threat to this country" and that citizens' hard-won freedoms were preserved.
"Too often government has got it wrong on all three counts and insecurity is growing as a result."
Mr Johnson said Islamist extremists had a "corrupt and perverted" view of Islam
Foreign Secretary Mr Johnson said Islamist extremists had a "corrupt and perverted" view of Islam.
"But now is not the time to do anything to subtract from the fundamental responsibility of those individuals, that individual in particular, who committed this atrocity and it is absolutely monstrous that anybody should seek to do so.
"I find it absolutely extraordinary and inexplicable in this week of all weeks that there should be any attempt to justify or to legitimate the actions of terrorists in this way."
Critics also noted Mr Corbyn's record of voting in Parliament against anti-terror measures, opposing military actions and sharing platforms with Irish republicans and Palestinian fundamentalists.
Defence Secretary Sir Michael Fallon said: "Jeremy Corbyn could be Prime Minister of our country in less than two weeks' time yet he has said only days after one of the worst terrorist atrocities this country has ever known that terror attacks in Britain are our own fault.
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Britain's opposition Labour Party leader Jeremy Corbyn speaks at an anti-racism rally in London
"There can be no 'buts' when it comes to condemning the unspeakable evil carried out by these extremists.
"Jeremy Corbyn has a very long track-record of siding with people who want to damage and attack Britain.
"At every stage of his political career, he has been soft on terrorism.
"The choice has just become even starker: it’s between Theresa May, acting to protect our national interest and keep our country safe, and Jeremy Corbyn, who is simply not up to the job."
Conservative candidate and former Army officer Johnny Mercer accused Mr Corbyn of "buying into the terrorists' narrative" that the west had provoked attacks when outrages like the 9/11 attacks on America far pre-dated events like the Afghanistan and Iraq wars.
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France had suffered grievously from terrorism yet had no involvement in the Iraq war, while Germany had been hit despite playing no part in coalition attacks on so-called Islamic State in Syria, added Mr Mercer.
Labour former naval chief and one-time security minister Lord West said: "We've got to be very careful when we talk about foreign wars of supporting, in effect, the radical Islamist narrative and myth … that because we're involved in war, that's why there is terrorism. That's clearly completely wrong."
Lord West had criticism of Britain in the aftermath of the Afghanistan invasion and intervention in Libya: "But let's not make the mistake of saying they're trying to kill us and destroy our society because of this because that just isn't true."
Corbyn critic Mike Gapes, seeking re-election as a Labour MP, said: "Daesh (IS) hate us for what we are, not for what we do. Our foreign policy is used as justification for their crimes. It is not the reason."
Nigel Dodds, deputy leader of Northern Ireland's Democratic Unionist Party, said: "Responsibility for terrorism lies where it always does, with those who carry it out.
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"Those who excuse, justify or celebrate terrorists only make the job of the security forces harder.
"Jeremy Corbyn has a long and shameful history of indulging supporters of both Islamist and Republican terrorism.
"His speech reminds us again that in no circumstances is this a man fit to be prime minister."
Labour Shadow Attorney General Baroness Chakrabarti insisted: "Jeremy was very clear that there is absolutely no excuse, no justification based in foreign policy or any kind of policy for the atrocities that we have seen.
"However, it is right that .. as a Prime Minster in waiting … he says to the military that when you are deployed abroad it will be because there is a clear need only and there will be a plan.
"Some conflicts are absolutely necessary, and others are sometimes ill-planned and potentially counterproductive when they are used and abused by terrorists as potential recruiting sergeants."