If the site owner doesn’t want threads from a certain site they can make them forbidden, as some are. The ones you listed are not banned, ergo, they are allowable.
The sites that I mentioned, aside from NR, are leftist. So, why complain about another leftist site when you have no problem with the other sites (as long as they pump out the anti Trump articles)? The only difference is that this article is anti Cruz. Ergo, nothing wrong with the posting.