The question is if it is actually causing material harm. Again, I'm not saying it's a good practice, just that it's relatively harmless when kept in moderation.
IMO meow is less offensive than the LGB, but if you don't think LGB in general, considering it's origin, is a even a tad funny, then you're clearly pretty partisan, and they are probably doing it just to annoy you, which means if it didn't annoy you, or you made sure they never knew it annoyed you, it'd probably go away. People don't tease people very long who don't give feedback and a rise.