Platonic like has a lot in common with sexuality. It's already been documented that people tend to treat attractive people better. So for example, a male judge may give a lighter sentence to an attractive male defendant, than he would give to a hideously ugly defendant.
Even when it comes to, say, Styxhexenhammer666, I have trouble watching his videos because he's just so freakin' ugly. Even if I agreed with what he was saying, it would be hard for me to stare at that face for very long.
In contrast, if there's someone who's attractive, male or female, it's just easier to look at them. And the more you look at someone, the more you start to feel a connection with them. Like in that exercise I was telling you about, where you stare into someone's eyes for a few minutes.
At the same time, it works the other way, too. The more you like someone, the more you may consider them to be a physically attractive person. It's probably an extension of the halo effect; you notice their attractive aspects and discount their unattractive aspects. In the manosphere, they say that if a girl has a nice personality, you can give her a +.5 on the 1-10 attractiveness scale.
Men and women are only somewhat different. Some of the same features that one might find attractive in a girl, one might also find attractive in a boy. That's the "prettyboy" or "trap" phenomenon. Some effeminate gays (not necessarily trannies, but effeminate gays) are probably deliberately trying to cultivate that confusion in the heterosexual or quasi-heterosexual neural framework/pathways/whatever it is that instantiates physical attraction.
(Also, what's up with tomgirls? A lot of men are attracted to them. Maybe it has something to do with the challenge of bringing out their femininity and getting them to see how much they enjoy their womanhood, kind of like how men want to take pride in getting a lesbian to realize that she's actually straight. Although personally, I think attraction to tomgirls is kinda bluepill, unless one realizes that this is a girl who has been pushed into being a tomgirl and actually desperately wants to break away from it and be barefoot and pregnant in the kitchen instead.)
Who hasn't had that feeling, especially in their youth, of liking one of their male friends enough that they just wanted to hug them? Who is to say that maybe some of the same chemicals, neural pathways, etc. involved in heterosexual love aren't triggered by platonic liking? And the gesture is slightly the same; it's a desire for touch and physical closeness.
The only difference is, one doesn't go the other 10 percent of the way to actually having sex with the person. So, maybe "no homo" just boils down to saying "Only 90 percent homo! Not that other 10 percent." Because all that really stops it from being completely homo is that one reaches a point where one says, "I can't go any further because I'm not gay."
I almost wonder if "no homo" came about because of feminism. Women started wanting to be desired for more than their bodies, because they wanted to be respected for the same stuff that men get respected for. So men got in the habit of saying, "I'm not just saying this because I want your body. I really do respect your mind." It's actually kind of alpha to say, "I don't need to supplicate before you, based on my physical attraction for you; if you're not top-tier, maybe I can judge your work the same way I'd judge a man's, because you're not even worthy of my notice; or even if you are top-tier, I can get playful with you and treat you like a bratty little kid."
"No homo" seems to parallel that, as though it's trying to tell a fellow man, "I'm not just saying this because I want your body; I actually respect your mind." In actuality, though, friendships can work the same way as other relationships, in that there can idealization and devaluation. So there's not necessarily a whole lot of difference.