They basically made note of what everyone gave (for thank you cards).

Since then, they have been talking to us (immediate family: me, my sis, dad, mom, etc.) and complaining about supposedly “cheap people” who didn’t give them a gift or who gave only $50, (our cousin, for example) etc.

What do you think about that? Is that kind of behavior normal, acceptable and generally expected, or is that totally ridiculous and rude? Something in between?

Thanks!
They basically believe that since the wedding was expensive, the gift should reimburse them. They did say it could depend on the person’s means, tho. To their credit — they said it’s cool for a single person to maybe gift $50. But they said an established middle class couple should double that.