Karen1959, don't step back from this site, just scroll past the 'clique'. Maybe they should read back through some of the many posts on here and see how collectively it appears that they enjoy being sarcastic, etc. You'll also see that they very often have interesting points of view that give food for thought even if you don't completely agree with them.
As for OP, I think we have brought our children up to be seen and heard, giving them a voice to challenge and fight for their 'rights." All of which is a good thing but when their views differ from ours, it is sometimes difficult to accept. Personally, I don't think you did anything wrong but trying to find a way forward in the future when the other DGC are receiving your gifts is probably the discussion you should be having. My own experiences with my DIL's show me the more respect I give to my DIL's points of view, certainly makes life easier in the long run even though I don't always agree with it. After a while, it becomes a non-issue because they learn to trust you and don't feel the need to fight you.