Remind them that it's your world, you find a lot of enjoyment from the a craft you like, woulld you like to only visit them at there home? So they don't have to see it when "Visiting" *your* "Home"... and the only time anything gets to be said is when your no longer around then they can complain all they want....
Agree to disagree and when they bring it up remind them it's not a topic you'll discuss, let them know it can be a larger supply ;)
LOL might even be fun to tell them every time you speak to them, or they get on you tail about it....you don't have time to chat your going to the fabric store :)