I do not know what triggers the filter. It appears to sometimes trigger from frequency of posting, other times because of aggressive or abusive language, and other times it just appears random to me.

But it otherwise appears to be the automod just auto-removing comments from the sub.

The reason you won't see [removed] in place of the post is because there are no replies to it. On rare occasion someone will get a reply out before the auto-mods hits the comment, and in those rare cases you will in fact see a [removed] in place of the comment, but only if you look up the 'context' of the reply from that user's profile. If you come into the comments from the sub like usual, you still won't see anything.

But you can generally see how active the filter is when you see "load X more comments." It's easy to spot when that's a small number, say 5 or 6, and when you click it to expand those comments, you only see 1 or 2.

As someone who despises Trump and his sycophants, I can say from experience that the filter is not anti-Trump or pro-liberal. I just can't nail down the specifics of the filter, and I'm fairly certain the mods prefer it that way.