No, David definitely meant the homophobic things he was saying in a bad way. I felt so badly for both Nick and Charlie in that scene and I kinda wanted Sarah to be a little sterner with David about the way he was behaving. Charlie definitely puts Nick above and beyond himself, including above his school work. It's not healthy, even if we're all obsessed with their love, but I think there's a reason why he would rather give Nick his pen back than be in his own classroom. I don't think Charlie's parents are wrong to set boundaries but Charlie is a teenager and restricting him like this isn't gonna do anything but cause him to rebel.