

Find some place… as an example, hexbear’s instance has c/slop… to drop a link to the offending user’s comment or post and whatever happens… happens.
You’ve got the option of Reporting the post/comment to the moderators. Which will require you knowing the moderation rules of the community in question to take advantage of.
Short bullet point/talking point responses. Replies with things like, “This is racist/sexist/genocide denial/etc”, then disengage. You don’t need to get into a long drawn out comment war/debat bro situation.
Make fun of them for being a goober.
The Israeli military should stop using Israeli citizens as human shields then.