Everybody seems to be offering a tiny thread of sympathy about the sister's wedding, but it was last year!! During a pandemic! "We are only going to a wedding this year if we're part of the wedding party" seems like a very reasonable boundary to set in 2020!

yes, this! I was just thinking of how to phrase this -- I didn't at all trust the way they reported the DIL's Outrage considering the swiss cheese that is the rest of the letter. I was thinking that making her sound like an Entitled Parent might be a way to frame a reasonable decision as unreasonable.