now i hope you don't confuse why black people did sit ins and boycotted places , it wasn't because of refusing to be served. It was for receiving second class service for the same price. Jim Crow shop owners were just fine having pick ups for black people in alley ways, or having a negro section in a shop. It wasn't about black people being allowed it was about taking the money and treating them like shit in return. This isn't the same thing, here we have someone saying they don't want to be a part of something that goes against their beliefs ie the wedding, he's not taking their money or refusing to refund (is he? that would be a lawsuit).
There are similarities but the difference is there, just as many boycotts of establishments happened as did , sit - ins to prove a point. Boycotts of bus systems, retail chains, etc etc , however in the mean time black people had their own businesses , and people to patronize. The issue was businesses expecting full PRICE for jim crow service. Things changed because businesses saw people voting with their wallets, if such and such a chain isn't going to accomodate black people then spread the word and give your money to someone who would.
It's a little disturbing to see that aspect of it being glazed over thats huge.