You’re drawing the exact wrong conclusion. Building an old boys network was acknowledged by society as a problem. If I, as a straight white male, started a men’s club, excluded women, and conducted my company’s business there, I would (rightfully) be exposed to a claim of discrimination.
The behavior is the problem. The exclusionary nature of these networks happens to be illegal in many US states, as sexual identity is a protected class. Doing the same nonsense at the Harvard club is equally noxious, not not illegal.
There’s a number of very significant, very problematic power brokers wielding authority in tech companies now. The fact that a significant part of the cohort is gay is irrelevant - the fact they have a clique that is insular and possibly corrupt is. That commonality is no less relevant than the PayPal Mafia.