Please remove me from your group text!

My brother in law can be a bit annoying at times. He has this thing where he'll send you a link to a religious video of some person preaching or something like that. It's not that I even asked for it. He'll just send it to me and 2 or 3 other people at random, thus creating a group text. And it seems that every time he does this he'll add different people so that now starts a new group text. Here's the thing. I have 6 other brothers and sisters and he never sends that stuff to them, or maybe he does and I don't know about it but I never see any of their names on the group text. Just a bunch of phone numbers who aren't saved in my phone. I have an android and sometimes one of the people's name will appear and even though I don't have them in my phone their name comes up. This morning there's a group text going around that he linked me to just to say Happy Valentine's Day. His sister is on it and an old guy from his old church is on it as well. I know because their names came up. Again, those aren't people I have saved in my phone. Would I be wrong to reply to the group text and say, "Please remove me from this text" or should I go back to the source, my brother-in-law, and ask him not to add me to any other "random" group texts. I mean sometimes I'll wake up and there will be a text from him with some random woman preaching and it'll be a group text with me and one other person. Other times he'll have 10 people on the text. It's like he just goes down his contact list and say, these people need some inspiration. What's the best way to approach this without coming across as mean or rude? Reply to the GC and ask to be removed or reply to the person themselves and ask not to be added to any other GC?