I specified factual, because anti-Trump blog post with opinions and theories without much facts do not get flagged. It is not that any anti Trump article is flagged, but the factual dry ones are more likely to be flagged.
I have seen maybe 1 pro Trump article being flagged. From what I have seen, they tend to be ignored rather then flagged.
If you don't have 'showdead' turned on in your profile, what could be happening is that those articles are so heavily flagged that they're almost all [dead], in which case only users with that setting turned on would see them.
Articles that show [flagged] but are not [dead] have actually been flagged less (relative to upvotes) than articles which get flagkilled, i.e. flagged all the way to the [dead] state, where they cease to be visible to most users.
I don't know what data you're looking at, such that you'd only see such a distinct subset of the total, but this is not true.
Non-factual and pro-Trump articles also get flagged—probably more heavily, in fact.