I don't think you were rude but even graciously rejecting someone can hurt their feelings. You have to decide if they're unsolicited communication is so annoying you're willing to hurt their feelings for it to stop. I don't think you have to accept everything anyone gives you but you have to be aware people will have feelings when you say "stop".
I disagree. According to this logic, we'd be held hostage by the
potential to hurt someone's feelings. These cartoons weren't drawn by mom, nor did mom pick out one or two that she thought the OP would like, she signed her up for them without asking first. Her good intentions don't make it any less annoying. Sure, she may be momentarily hurt that something she thought the OP would like actually wasn't appreciated, but she'll get over it. It's nothing. She put literally no effort into it. If this kind of thing seriously impacts their rel
ationship, then there was something wrong before this issue came along.
In a similar case, my parents bought me a weekly subscription to a religiously-oriented publication for a community that I no longer live in. Technically it does address the community where I do live, but I'm far enough away that my community doesn't get mentioned much. More importantly, I'm not religious, and it is simply not of interest to me. Most of these go straight in to the recycling bin. My mom didn't even tell me in advance that she was signing me up, or I would have told her not to, so when she asked how I liked getting Publication, I was honest and said, "Did you get that for me? I wasn't sure. Actually most of them go right into the recycling bin." I've spent a lot of time and energy doing religious activities with my parents, but finally I decided enough was enough and that I'd only do it when I wanted to, and this includes not being fake-grateful for a gift that she knows is not of interest to me, but has more to do with her encouragement to be more religious.
Sorry, no. People don't get to decide what you'll like, force a 'gift' on you, and then be hurt when you reject it. Or, at least, you're not rude when you ignore all said parts of that equation.