I don't think they're completely bullshit, but I do think they're not all-encompassing. I'm prepared to say that the descriptions for NT and NF are fairly consistent with the types' behaviour and thought patterns (insofar that NT and NF types basically will act in the way they are defined on Wikisocion).
Nonetheless, I'm not prepared to accept certain facts about the SFs or the STs. I'm inclined to think that the description for the ST club fits Delta STs quite well, but not Beta STs. Likewise, I think Alpha SFs could clearly identify themselves as being a part of the SF club, but I doubt Gamma SFs, especially ESIs, would find that the description resonates well with them. Regardless of the (most recent) controversy over my type, I'm Se leading. And I can tell you now, I identify with neither the SF nor the ST description. NT resonates far more with me. And I bet you'll find plenty of others on here who have the same issue as I do. To be quite honest, I've never discussed manual work, engineering or sports in my life. I find these topics incredibly dull. I'm far more likely to engage in political discussion, or philosophical discussion on some levels.
More than "general trends", I think they're wrong, and I think they need changing. Instead of "This kind of group behavior, though, in terms of seeing a club as any kind of unit, is visible only as long as the group is held together by, and focuses on, discussions and activities of their common interests. Longer and deeper interactions make such a club visibly "split" into the two quadras, n quadra and n quadra", there should be more detail about the clubs in their respective quadras, and the description about what Beta STs and Gamma SFs discuss and focus on should be changed.