Are my Christian parents reasonable?

I am in marching band and the theme of our show is voodoo. I honestly did not like it but my parents are going mad about it and won’t let me purchase fan shirts to support my friends and making feel like a scum. When we received our shirts for our show they said they will BURN it once we don’t need it anymore. I feel bad because the shirts are nice and holds many memories. They also don’t support our fundraisers and want nothing to do with our band.