I know what you mean. There is a pet store nearby that has some fairly rare, expensive, and hard to find fish but every single stack of tanks has ich and I completely refuse to buy anything from there.
I would like to add something that made me feel happy. I went to walmart the other night and their 3 stacks of tanks were in similarly horrible condition. There were two employees of the graveyard shift that noticed one of the oscars dying and were frantically rifling through the medications trying to find something that could help even without them having any idea what was wrong. They felt really really bad for the sick oscar that it restored some of my faith in people. I was able to point out some of the obvious sicknesses in the tanks and they started taking care of it as well as leaving some notes for their manager that was scheduled to come in during the AM.
We chatted about fish for a while and I referred them to my LFS that is pretty good in helping out since they had tanks of their own. I didn't think about recommending that they come here though