According to Wikipedia, Neurolinguistic Programming is a pseudoscience and dismissed by most experts. However, Psychology Today, a popular magazine, appears to not thoroughly reject it. Does this fact invalidate the legitimacy of Psychology Today?
A similar question has been discussed on the Meta site associated with this Stack.
In summary: Psychology Today doesn't really have any legitimacy to invalidate in the first place. It's just a collection of blogs without any peer review process.
Psychology Today is a popular science magazine, not a peer-reviewed publication. There are some good articles on the site; there are also many bad ones. Some articles cite peer-reviewed literature: if you find a peer-reviewed source on Psychology Today, feel free to read it for yourself!
The editors may keep certain content off the site, but they are not adhering to any standards of evidence or standards of clinical care. It's fine to cite for a source of popular claims, but doesn't have any scientific weight.
The main purpose of the Psychology Today website seems to be as a paid directory for psychology professionals - basically, people sign up, post their pictures and biography and a phone number to try to collect clients.
Some of the editors have brief biographies posted - it seems clear that the editorial staff have their expertise in publishing/journalism, like you would expect for a popular magazine. They do not have the sort of editorial staff that a reputable journal has, which would include university research scientists at the top of their research field.
In their media guide for educational advertisers the site compares itself (favorably, from the viewpoint of an advertiser) in terms of # of viewers to sites like The Atlantic, Oprah, Time, The New Yorker, Fortune, Popular Mechanics, and National Geographic. Many of those sites also have some good content, but may be more readily recognizable as popular magazines. If they were a site for reputable science content you could expect that they would instead compare themselves with other peer-reviewed content.
Many of the pages have language along the lines of "Verified by Psychology Today" but in every case I see this it seems to refer to their directory of psychology professionals rather than any of the blog content. I don't know what the verification process entails.