seebs said:
Evidence of Satanism included "red pillows, especially if they have tassels".
HA! I'm reminded of nice turn of phrase from Barbara Holland, describing a 19th-century redecoration of the White House:
Everything that could be gilded was gilded, and everything else had tassels on it.
(In a later edition of the book, "gilded" was changed to "painted gold", which just goes to show you the state of American literacy.)
But anyway, that kind of thing is surprisingly common. When you teach people that everything is black or white, good or evil, of God or of the devil, they end up making that kind of judgment. Red pillows, especially with tassels, must be of the devil. As good soldiers of Christ, they must be constantly on guard against attacks of the devil, and so they see him under every rock and around every corner and -- more unfortunately -- in most of their neighbors. In such hands, Christianity becomes an angry, fearful and superstitious thing: can't you just hear those parents saying "Bob played D&D and almost became a Satanist"?
When I was 16 and wanted to do anything my parents didn't want me to do, I always did it anyway, and tried to make sure they didn't find out. But I just can't advise the OP to be sneaky. My advice is to try to reason with your parents -- though that doesn't seem to be working -- and if all else fails, just bide your time. You'll be 18 soon enough.