Karen Zolciak is not having an easy time with this wedding. First she wasn't allowed to do any decorating, then there were all the restrictions on her dress, and now she's threatening not to come to the wedding after Kim sneakily did the tasting without her.
It's hard to say who's right or wrong, because it's Kim's wedding and she's paying for all of it, so yes, she can do what she wants. And yes, saying that you'll be sick and won't be coming is rather dramatic. But at the same time Kim should have probably have been honest and simply asked her not to come.
Kim should have just snapped a pic on Chanel in her wedding wig and sent it to her mother saying, "Do you really want to miss this?" Because the answer is no.
You are absolutely right that Kim should have told Karen she didn't want her at the catering thing, but the results would have been the same or worse. It was horrible that Karen's hissy fit kept her from supporting her daughter and meeting the in-laws. It was vindictive and childish and I wouldn't have taken pictures of those dresses to save my life. I'd tell my mother to wear whatever the hell she wanted but not to expect to be in any family pictures unless it's appropriate.