At best, the alumni seem to have two things confused. If they're concerned about a lack of ideological diversity on the campus, then listing all the left-wing activities of the faculty, and their voter registration, has some relevance, I guess. But it's not because it's wrong to be a Nader voter or a pro-labor activist, anymore than it's wrong to be a white male -- it's just evidence of insufficient diversity when you have a wildly disproportionate number of either.
On the other hand, if you want to focus on faculty doing wrong, then asking for tapes of professors bullying students in the classroom makes sense, but the other stuff is irrelevant. The UCLA project seems to conflate the two in an unfortunate fashion, suggesting that left-wing activism by faculty is somehow comparable to bullying students over ideology, which it's not at all. By doing so, the UCLA alumni hurt their own credibility.