Prosecution witness Michael Bexhill, who is using an alias, was accused of encouraging Muktar Said Ibrahim and Yassin Omar to fight in the jihad.
Mr Bexhill earlier told Woolwich Crown Court that Mr Ibrahim and Mr Omar were fanatical and radical Muslims.
Both men, plus four other defendants, deny conspiracy to murder and conspiracy to cause explosions.
Mr Bexhill told the jury the two had gone on training camps in Scotland, along with a third defendant, Adel Yahya, who had "aggressively" tried to persuade him to fight for jihad.
But under close questioning from Ibrahim's counsel, George Carter-Stephenson, QC, he was accused of being the "more extreme" in his attitude towards conflict in the Middle East.
The barrister asked: "Weren't you the one that suggested that people should go to fight the British and the US troops in Iraq?
"You were the one who extolled the virtues of young men taking up arms in places such as Iraq and Afghanistan.
"I am going to suggest that you were the one with the more extreme views. Ibrahim and Omar had less extreme views than you."
To each suggestion in turn Mr Bexhill gave the same answer: "No."
Mr Bexhill was asked about the jihadi videos they watched while he lived with Mr Ibrahim in north London, at the end of 2004.
"They were trying to brainwash me, that's all I can say," said the witness.
"I am going to suggest that any brainwashing was the other way round," replied Mr Carter-Stephenson.
"No," replied Mr Bexhill.
Mr Ibrahim, Mr Yahya, and Mr Omar are among six men accused of carrying out an extremist Muslim plot to cause chaos on London's public transport system.
Their co-defendants are Manfo Asiedu, Hussain Osman and Ramzi Mohammed.
All the men deny charges of conspiracy to murder and conspiracy to cause explosions likely to endanger life.