I really don't believe it is the people's fault, I mean, these people have been under a regime for years, they were brainwashed, tortured, killed, I'm not surprised that they would start hating another countries and stuff because their leaders tell them to. They need democracy they are obviously tired of all the bullshit and they woke up because of Egypt. I don't think they really have this hate for America or any other countries, and you can't rly think "would they do the same for us", maybe, maybe not, does it really matter? I believe we should help the ones that need help, it just makes the world better, even if they still hate you at least you know your doing the right thing.
There is also another reason why some demonstrators are hating the US, most of the weapons used against them were made in the U.S or given by the U.S idk, so if you saw a teenager getting killed by one of your rubber bullets or one of your shotguns I think you would be pretty pissed cause you would think "oh so the U.S makes the weapons that kills our kids".