You could say that about anything, though. Everything has it’s proper place. I didn’t say that the wedding is a show, I said it is all about the bride and groom. No other day would they have trouble getting to sleep the night before, wake up in the very early hours of the morning to tend to their appearance for hours, work to make sure everything will go smoothly, go to the service, go for a very lengthy feast with speeches given about themselves, be the main attraction for a dance, stay for a drink then head to bed in the early hours of the next morning.
A wedding is hectic, it is totally focused around the bride and groom. This isn’t a bad thing in and of itself, this is just how weddings are, but to be done on a day when “the faithful are bound to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord’s Day, or the proper relaxation of mind and body” (ccc 2193) is just a completely improper time.
Put it this way, it would be a fault for them to ever say “remember our special day” with the wedding on this day. It really could have been any other day of the year.