I was just speculating about how society would view a hypothetical cult of white western terrorists, who took some fundamentalist concepts and twisted them into a politicised ideology of hatred.
There was massive venom directed at Irish Catholics in England during the mainland IRA bombing campaign. Inaccurately, because Sinn Fein are about as not-Catholic as you can get, it was widely assumed that Catholics were supportive of the IRA and vice versa. People like Vincent Nicholls routinely had to condemn the IRA for this very reason.
This was the opposite problem to the one Islam faces: in the case of the Islamic terrorists, they claim to be Muslims, other Muslims disagree, general population lumps them together.
In the case of the IRA, they never even pretended to be Catholic, their ideological position didn't support Catholicism in any substantial way and the cause for which they were "fighting" was entirely political. Gerry Adams couldn't give a shit if the six countries are Protestant, Catholic or Scientologist, his cause was reunification, not conversion.
But it was enough for the general public that they came from a largely Catholic community and (as a first approximation) Catholic/Protestant is a reasonable proxy for Nationalist/Unionist and a better one for Republican/Loyalist (ie, your typical IRA bomber would have been raised Catholic and, if he went to church in between blowing shit up, would have gone to a Catholic one).
If you think that Catholics in British cities, particularly Irish Catholics, weren't held responsible for the bombings by the IRA, I've got some burnt out houses to sell you.