not the yes/no pet policy, but breed selection politics. IMO, if you're going to be pricks about deciding which dogs can and can't be in your building, then actually have a case ... no, a working class dog probably won't do well in a small apartment in a big city, no, you can't have your 2-year-old dalmatian hang out in the apartment for 12 hours a day while you're out at work, and if you don't want an "aggressive dog", then my mother's yorkie wouldn't be good in your building ... and on and on and on. Or make it case by case even.
I'm not a fan of the blanket "no pitbulls, no rottweilers, no german shepherds", which is what happens all the time. I think some of it boils down to landlords not wanting "undesirable" people in their building, and this is one way to help that.