I think we're beyond the point of "you can't criticize them. That's mean and motivates them." At what point is the line drawn? Should it be in bad taste to criticize Orban supporters because it makes them support him more? What about Erdogan? Putin? Kim Jong Un? And why is it one sided that they can't be criticized, but it's all fair and good for their own leaders to demonize everyone? It's a silly double standard and people see through it now. Concern trolling stopped being effective years ago.
If you want to win elections, yes. You never convince voters by telling them that they are evil people. Its fine to say Trump is evil, its not fine to say Trump voters are evil because those voters will now be much less likely to vote for you. They can't take back their votes, they already voted for Trump before, so they will just not vote for you when you attack them like that.