How's it not good for the bike or the car? I do it all the time; lay the bike on its non-drive side in the back, wheels on. For two, I cover the first with a doubled moving blanket and lay the second on the first (carefully).

I have hitch racks, but it's much easier and IMO safer for the bike simply to "throw" it in the back. I only use a hitch rack when I'm carrying a lot of other gear and can't easily fit the bike(s) inside.