You have a solid point, and I'm not being sarcastic. I dunno, I envision this thumbs up as more of an, "You march on, dude. We're in the trenches together, fighting for justice! Fight, fight on!"
If it was closer to, "Heeeeeeeey there" or "HAHAHAH NICE WORK, CHUBBY" then yeah, I'd be mortified, and possibly stabby.