Cops, taxes, and people's unwillingness to fight cops or taxes.

All rules are made up. HOA neighborhoods require people to sign a legal contract to follow HOA rules for them to be recognised as "home owners".

The legal definition of "ownership" is, as always, made up, and in this case it means the state will let the HOA violently force you out of the house if you don't obey them.

More precisely, HOAs operate in deed-restricted neighborhoods. When you buy a house in that neighborhood, you sign paperwork granting the HOA authority over your property and the right to enforce rules and fines usually up to and including seizure of the property. It’s literally written into the deed to your house that they get to tell you what to do.

The deed of the house states you have to obey them, basically. It's pretty bullshit.

Binding contracts.