Did she mess up or were the instructions for Secret Santa unclear?

This year we decided to do Secret Santa for the adults and gifts from everyone for the kids (4 kids, all aged 5 and under). We sent out instructions around Thanksgiving as follows:

"Hey everyone! This year we decided to do Secret Santa. We will be drawing names at Thanksgiving. The limit for gifts is $75. Please come up with some items you like (for example, books by Catherine Cookson, vanilla scented candles/body creams, gift cards to Sephora, chocolate, etc) and post your "wishlist" in the family chat. Merry Christmas!"

Tonight we exchanged gifts and my mother-in-law got mad that only her Secret Santa got her a gift. The grandkids all made her homemade gifts because they're all 5 and under. She is divorced from my father-in-law but he still buys her a box of chocolates every year. She then tells everyone "Well I guess none of you all are getting your gifts".

Now I have my mother-in-law who is completely upset because she feels under appreciated by her kids (all aged 30+), and now the kids are all mad at each other because they're like "We didn't discuss how we'd all feel"

I'm like... Were the instructions unclear? Everyone loved this idea in September. Everyone was saying in November how easy Christmas shopping was. Everyone bought only one gift for the family gift exchange. What you buy your spouse is up to you and we all decided to do that exchange on the 25th privately.

Soooooo.... Anyone do this and how the heck does it work for you?