I don't know the details or the bills, but it isn't uncommon for people in contested seats to be allowed by the party to vote in a poll-favorable way when their vote won't change the outcome.
Simply, counting 'Times voted with Trump' doesn't say much that is useful and can be misleading, especially in the context of a post about death threats to politicians.
Social media can have a very us or them mentality. If you're not 100% lock step with the group then you're an enemy to be scored and attacked. I read that comment as 'Yeah, they're getting death threats but they voted with Trump so they deserved it ()".