I suspect you are closer to a true "alpha male" than the *******s you described.
A true "alpha male" looks out for the group, communicates effectively, treats women with respect, etc. Most importantly, a true alpha lives by his own code. He leads the pack, he doesn't follow it.
Vain frat boys aren't alphas. They are betas or omegas masquerading as alphas. This is very noticeable by the difference in their behavior between when their friends are around versus a one-on-one situation. There's a lot of insecurity and overcompensation going on with them.
I usually avoid people like that because they're sad and boring. If I found myself running into those types of people often, I would change where I hang out/who I hang out with, to be honest.
If these are work ppl, and you have no choice, then just be up front with them. If they tell a joke you don't like, don't laugh. If you disagree with something they say, tell them why. i.e. Be a true alpha and they will have no choice but to respect you.