Jesus Christ. I can't believe some of the **** in here seriously.
You guys are seriously saying you can't have friends due to their anatomy?
There are a lot of posters who feel exactly that, yes. Some have probably been burned in the past or seen it happen to friends or family and some inform themselves via eye-wateringly delusional sites, e.g. r/MRA on reddit. I could list you, with a fair degree of certainty, 7 posters who fall into one or both camps.
I think that this is one of those things where your experience or experience-by-proxy absolutely determines your view to the extent that the other view is impossible to understand. For example, and to further Fox's and tom_e's point, I would have no problem at all with my wife going out for dinner with a male (or female) friend. I have nothing to worry about so even using the word 'problem' is making it sound something it isn't. I trust my wife, she is a good and honest person, and enjoys spending time with her friends, in the same way that I do with mine.
That isn't 'beta', and it's not 'naiive'. It's an understanding that partners can and should spend time with other people. My wife is not an asset or something to be controlled and limited, and to go back to my earlier point about experience shaping your view, that's where I stand.
If you're unironically using words like alpha, beta, gamma, and white knighting then I can't really see eye to eye with you on this. The logic doesn't stack up, much like my view on it doesn't stack up to people like tosno, robgmun, wildman, em3bbs, Locky, sega man dave, and gabbatek.
And I'm ok with not being in agreement.