HOAs can be incredibly difficult to deal with. I am fortunate to live with one which doesn't charge fines (yet), but rather sends escalating warning letters eventually leading to a property lien if the problem isn't fixed. My own AirBNB experience was resolved with a phone call where I explained the circumstances of why I was renting rooms, which was essentially connected to a nasty divorce and an agreement for me to keep my house. The HOA knew that if they played hardball I would have my home seized and they didn't want that because then they have one less paying dues member and a vacant property for months until a bank auction.
With that said its critical to know the HOA rules especially if you live with an HOA that likes to fine people. HOA fines also might be illegal within themselves, especially if its proved the HOA is trying to make revenue. Also, if they did covert investigating to identify your AirBNB property listing, had people stay there falsely to establish it was you and your home, then that is a serious invasion of privacy.
For all those things, definitely get a lawyer. Preferably try and find one who will not work hourly but rather a percentage for a countersuit towards the HOA.