I have a good friend in Manila, a programmer like myself, who was very clear about his feelings toward Americans, I could feel a lot of resentment in his feelings towards American people in the Phils.
He was clear that he preferred the British but then he was working for a British/French company in Manila he is now working in Dubai and seems quite happy there.
I have also known one American that used to live in the same building as us in Manila and he at first seemed like a nice guy but after a while I saw him being extremely rude and abusive towards the locals, quite literally standing in the street giving a local person the finger and swearing at them. I also had to suffer a tirade of his abusive opinions about the Philippines while sharing an elevator in our building on more than one occasion. A real shame as he seemed quite nice the first time we met him.
The problem is that all of us will form opinions from limited experience and we tend to fall into the mistake of using stereotypes as a substitute for proper thought, I am guilty of this as well although I try not to be.
For my own part, one thing that really does get to me, I really hate it when I am walking down the street and I get the "Hey Joe" from the locals, I always want to make it very clear I am not American, indeed I want to make it very clear I am Scottish
It's a bit of the old Scots - English chip on shoulder thing and an extreme desire not to be associated with crass Americans and I am sorry to say I suffer from it a little bit, I should be better than that
Sometimes the "Hey Joe" can feel a bit sinister but usually it's just surprise on their part that I am walking around what is maybe a poor neighbourhood. I usually exchange a smile and a bit of friendly banter but sometimes I have been scared.
In general I don't remember any direct personal abuse apart from the odd occasion when I have felt threatened by a taxi driver demanding over payment but that is only a worry when the taxi is dropping you at home elsewhere there is less need to be worried.
The lack of abuse is actually one of the things I really love about the Philippines, so while I think there is a bit of a problem sometimes it is really small.