I'll pile on, no problem. Because as COL Schlichter points out, that's exactly what they would do to you, and we are playing by their rules.
The argument for being nice is that 1) we should live the way we wish to live, that is, model the way we want the world regardless of how the world actually is and set the example; 2) we are better than that; and 3) Jesus tells us to. Of these, No. 3 is the most compelling – the hardest part of Christianity is loving your enemies. Perhaps you can do that even as you tweet that the fifth rule of gun safety is never give Alec Baldwin a gun. Jesus wasn’t a pinko hippie; he confronted and told hard truths. And despite the injunction to turn the other cheek, Christians are not pacifists. After all, many soldiers are Christian and they kill their enemies, so you must be able to be a Christian and point out through biting sarcasm that Alec Baldwin is awful too.