The term alpha/beta is used because its a simplified generalization for a complex concept so its more easily grasped and understood. Obviously being over simplified its not necessarily entirely accurate but that's never really stopped any one before. As for the others I have no idea.
I'm too old to find that shit amusing. Same goes for using bae... are you seriously that fucking lazy you can't finish saying a word? I don't even know what mirin means, to me it's rice vinegar. I don't want to know either... like I said, I'm too old for that shit.
Because they care too much. If people worked more on their own abilities, confidence, even appearance and stopped believing in the alpha/beta shit they'd have better results and stop feeling sorry for themselves.
I don't know bro I just hate the fucking beta cucks who don't lift on here. Sloots will always choose the alpha male. Betas are just bitter and straight up mirin my girl @BiscuitesSwag 's joocy ass arms. We are going to go sloot slaying this weekend.
Honestly it's all just for jokes. I know users on here who use the terms and I just started doing it occasionally for good fun. It's nothing to get too cheesed about, just don't read it. They're not technically doing anything wrong.
It's the sign of a rare brain disease caused by too much heavy lifting. As their brains begin to rot from the inside out, they begin parroting those words. Terribly sad, as they eventually lose the ability to use any other words.