No, they don't fine you, they put a lien on your property for the breach of the agreement and you can end up getting your house sold out from under you.
This!
Each HOA is different, just like every 'hood is different. Some are great places to live, some are a nightmare. I find that the people who talk the worst about them have never lived in one. The benefits far outweigh not being able to put my car up on blocks in the driveway or paint my brick pink.
As a board member on my own HOA, I know mine would say "no" to running a business out of your home, the fact that it would be firearms is moot.