A vote to treat people badly is _absolutely_ a good reason to be angry at someone.
If you're voting to take away people's healthcare, or to discriminate against them based on who they love, or their gender, then of course they are angry!
If you're voting to take away people's healthcare, or to discriminate against them based on who they love, or their gender, then of course they are angry!
But it's fair to expect that you won't get into a fistfight with someone just because they make you angry.