It's mostly just apartments and other corporate controlled places. There are tons of homes rented in most cities by private landlords who won't bother to do any background check. Many won't even care if you present yourself as a civilized person who nobody would ever expect to be a criminal.

The problem is many people with records do not know how to properly carry or present themselves, so they end up getting judged by their appearance or their mannerisms to a greater extent than the average person. If you have no criminal record, you can look like a bum and easily rent at many different places, however with a criminal record, you cannot afford to look like anything less than a perfectly civilized member of society.

While it's true many apartments automatically deny based on criminal record, every single felon I know who has found persistent difficulty finding housing was the kind of person who didn't carry themselves in a "normal" way. Whereas, I know plenty of felons with very serious charges (like manufacturing methamphetamine), who were able to rent homes easily without issue, just by carrying themselves in a highly respectable manner.