Believe it or not, the 12 day war between Iran and Israel was exactly that, and the reaction of the Iranian people was not as uniform (in either way) as one might guess. You could walk on the streets and see some "Hit them Israel" and other similar writings on the walls (the Iranian people were not exactly pro Israel before the war). And yet people could not sleep due to constant bombardment, they had to follow the evacuation orders by the IDF etc.

You mean I would hate people more and call them fanatics, terrorists and rapists without knowing anything about them? Do you think that would help?

Except sometimes it works in the other direction. Quite a few of my friends while sheltering from russian bombs in Kharkov still cheered russian efforts to annex Ukraine.

I don't think you can guarantee that. Yes, you might have a strong prior in favour of that - most people don't have a propensity to prefer logical and systematic reasoning over strong emotions such as anger or hate - but it's still rather unfair to a person you're talking to to assume that must be the case.

Yes, when people are badly hurt, they will often lash out in hopes of hurting someone else, using the flimsiest excuses to justify it. It doesn't make it right or a good idea, though.