YU is literally Modern Orthodox since Modern Orthodox, unlike Yeshivish, has an actual organization with YU taking up a massive percentage of its head. Whether or not they are frum is a different discussion.
The Yeshivish community has written them off decades ago, I’m not sure what sort of association you expect from them.
As for their “Chaveirim Kol Yisroel” club, I don’t see this as any different than the club that existed in Cordoza for the last several decades.
The language they used in setting it up basically states that it’s a support group for men that don’t have tayvas nashim, or women that don’t have tayvas anashim, and how to live a frum lifestyle with that. Which is fine, I guess, assuming they stick to the charter. Obviously, I’m not stupid and I know that they will be hosting talks, publishing media, and holding events that go against halacha. But until that point, and until RIETS officially endorses such activities, we have to be dan l’kaf zechus.