Now that Vernon has lost his fight to “protect” Harry, he (and Petunia and Dudley) just turn mean. I mean, dropping Harry at the non-existing platform and leaving him there, laughing at him, that’s just mean. Before that, there was at least a warped sense of honor involved for Vernon. I guess this is his way of regaining his dignity. (he had the strongest agenda before, so I’m assuming that Petunia and Dudley are taking their cues from him now; this was Vernon’s idea.)
When Harry asks Hagrid why wizards hide from Muggles, Hagrid replies, “Blimey, Harry, everyone’d be wantin’ magic solutions to their problems. Nah, we’re best left alone.” It’s interesting because there’s no sense of fear. Also reminds me of later when Harry will write an essay on that witch that was supposed to be burnt at the stake but just made a joke out of it. The wizards are extremely isolationist, but they are like that out of a sense of superiority. That’s why Arthur’s interest in Muggles is considers so quirky, too; it’s like when somebody studies turtles, weird, quirky but harmless. Anyway, it’s a perfect breeding ground for an anti-Muggleborn attitude. In this world where Muggles are a nuisance at the best of times, of course a lot of people would consider Muggleborns inferior as well. And while a part of the wizarding world is fighting anti-Muggleborn attitudes, nobody is giving a fuck about anti-Muggle attitudes. Hagrid, of all people, has them. Everybody has them.