1) Citations should say what they are claimed to say.
2) There are reasons to doubt a citation, even when published from a well regarded source. If they do not link further to primary sources, or if they link to an unreliable primary source, note that. Follow the stream of citations up to its source, lest you wallow the accumulated detritus.
Example: Why would you cite a publication that cites Twitter, when you can just cite the Twitter post itself? This can only add an unwarranted aura of credibility.