I don't think this sort of cynicism about LGBT rights activism is helpful. If we want to make progress in this area, we need support from all sectors of society. That definitely includes people who aren't saints and who don't act from wholly disinterested and pure motives. Whatever his motives (and I can't read his mind – can you?), Marc Benioff did something substantial to support LGBT rights when many other CEOs did not.
There's no objective content to the accusation of "virtue signalling". It's a zero-effort means of objecting to whatever kind of activism someone doesn't like. Instead of making a substantive criticism of the activism itself, just jump to uncharitable conclusions about the person's inner motivations.