>why doesn't Constitution apply to homeowners' associations (HOAs)?
State laws govern HOAs and some require due process and other state and/or federal Constitutional protections to the homeowners. But without a statute like that - or establishing the HOA is a state actor (e.g., they accepting subsidies for energy incentives or other schemes - where one may be able to argue they have become extensions of the state), then Constitutional rights can't be enforced between private citizens. State crimes can. Fraud, breach of contract, violation of governing documents (CC&Rs, policies and procedures, etc.), conduct unbecoming of board members, slander, libel, money crimes, breach of fiduciary and other duties, etc.- are all available, and more. But HOAs usually protect themselves with (possibly unenforceable) one-way attorney fees if unsuccessfully challenged, draconian restrictions against what documents a resident is allowed to see (if not a board member), let alone surveillance footage. They can look for what they need all day in the footage, but homeowner is not allowed to see it - even if defending self against a compliance issue or other claim.
HOAs response is: "If you don't like it here, you can leave."
Or you can run for the Board with like-minded people and change the policies and/or their application.
But the unavailability and/or attrition of good people, just like in other forms of government, and the soul sucking noises and actions of the power hungry parasites are always available through the revolving doors to fill the open board seats. They live for it. And they benefit from it.
Microcosms of our corrupt state and federal governments.
And just like fed and state governments, if the parasites are voted out, they bide their time, knowing they will be back. And like the cockroaches that many of them are, they always return.