The law explicitly says you can’t discriminate housing ads against certain groups. Courts have held that Things that aren’t illegal on their face can be illegal if they have highly discriminatory effect in practice.

So I don’t see why any of that should be allowed here.

And it would only apply to things that have a heavy discriminatory effect. I don’t see why it would matter if you chose not to advertise your non-pet friendly apartment complex to people who have pets. Unless someone can show that’s a pretty direct proxy to a protected class it seems fine.

Again, this only applies to kinds of ads covered by this (or similar) laws. Housing and employment are the only two kinds I know of. I see no reason why you should be restricted in who you choose to advertise your new T-shirt to.

It’s not just (presumably) his position, it’s the law. And there is a good reason for it. Look up red lining.