Removing them would be the same as fixing lightsaber rotoscoping, or jump cuts, or fixing the black R2 in space, or anything like that - they're there because that was the state of FX technology at the time. If you're for preservation, then why wouldn't you want to preserve them? Preservationists are for no alterations because they want the film to look like it was made in 1977. Why? Because IT WAS. They didn't have the technology to remove/not have garbage mattes in the first place, at that time, so removing them would be undermining the whole concept of preservation.
If you can't see that, Rob, then there's nothing more I can say. I find the horrid saber effects much more distracting, but I'm not clamoring for them to be fixed because that's not preserving the film the way it was made in 1977.