Hence, you cannot participate in any of the contests or challenges.

That's not quite true. There are certainly Communities where it is a valid condition. In others, other qualities are valued. It is best to have a look around the respective Community before joining: You will find the rules and customs everywhere and then decide whether they suit you or not. I wouldn't impose myself on others; rather find your niche where you are appreciated and recognised as a good author.

By the way, you can take that as a compliment. I don't know if you only like to write about ghosts and mysteries, but you certainly do that well ;-))