I could see that causing intense jealousy for Zach, but what I found so nasty was how ALL the girls treat Zach during the game. The "lick/kiss your own hand" kind of thing. It's a party drinking game.....I know that scene probably wont offend the typical f95 player because they gobble up this kind of "cut other guys down to ensure mc success", but I found it way too mean-spirited.
You are ignoring the fact that Zach's prior behavior affects how he gets treated by that point in the story. He had been constantly annoying Layla and pursuing her for months(a while at least so him being annoying isn't new behavior) and constantly calling her babe and other shit, even when she expressed very clear disinterest in being with him, and showing that he isn't interested in her as a person but a fuckable object. This gets further highlighted with the immediate interaction with Alexis in the bar on the first day at the school too. Like, yeah of course she isn't going to be super pleasant to someone like that after a while and to be honest she's way nicer in comparison to her best friend Elena, which again of course she doesn't like Zach because she has watched him be a douche for a period of time to her best friend.
This isn't some crazy unrealistic character type either, there are plenty of kids in high school that annoy others this way without even realizing how shitty and wearing their behavior ends up being after a while.
When you act like an asshole you get treated like an asshole.