I think it could be because his ex-wife Marcia Lucas edited the original movies and even won an Oscar for ANH while George Lucas lost. The SE were re-edited by other people. It could be because George hated his ex-wife, and it really sucks to be jealous of someone you hate.

I have heard a funny/sad thing about his ex-wife (depending on your point of view). If you ever get to Skywalker Ranch, you should never ever say ANYTHING about the stained glass windows. If GL happens to be nearby and hears you, you would be thrown out at once and banned for life.
The reason is that his ex-wife married one of the guys who built the windows ...
I was amazed when I heard this the first time, but it has been confirmed by several people.