Question

[Belacqua]

Alpha means like "masculine" and beta in this context means not alpha. This terms are common among posters from a Pick up Artist or manosphere background.

Come to think of it, they're kind of using the old, pre-modern categories.

Before people were categorized as "gay" or "straight," they were thought of as active or passive. So a man who enjoyed fucking men (a top) was considered masculine, and this was considered "normal," not "gay." Because it was assumed that men will just put it in anywhere they can. But a man who enjoyed being on the receiving end was considered feminine (which for a man was bad). 

So being a "real man" involves taking the lead, not accepting someone else's. Being a porn consumer probably seems too passive to them.

The whole "manosphere" is alien to me, but it probably goes way back in one form or another.