I'm unequivocally against this. Firstly, the ones without Ukraine flag emojis in their Twitter bio don't deserve such a cruel fate. Secondly, the war will be over quicker if the Kiev regime has less bodies to throw into the meat grinder.
Edit: Similar things have been proposed in Europe too by the way, and here too it is both morally and pragmatically correct to oppose this idea.
Even if it means we have to continue to see their stupid flag-waving and keep hearing the same idiotic cliché phrases on repeat from all the annoying Ukrainian keyboard warriors who are cheerleading the war from the safety of western countries.