Hurt feelings over wedding invite declines?

It sounds like you are taking the wording on your on own RSVP cards too personally. Don't assume that just because they checked "decline" or whatever it says, means they aren't bummed or disappointed about not being able to attend. It's just how RSVP cards work. They may have legitimate conflicts and feel really disappointed that they can't come.

The worst is not the people that decline but the people you have to track down to get a decline response to make sure their invitation or response card didn't get lost in the mail. It's one thing if you invited 300 people, and half of them are extended family you don't know that well. We kept the invitations to 70 people we feel we are close to and really want to honor by throwing them a party. To have them not even bother to return the RSVP will put those friendships on a lower rung from here on out. There is no other way I can feel about that. We are private introverts that invited only those we consider to be our close family and friends, not for gifts but because we cared enough to invite them. How hard is it to drop a card in the mail that already has a stamp on it or even to send a quick text or social media message before the due date, or even to navigate to the web address provided on the invitation and decline that way? We understand other obligations or lack of funds. At least now we know who actually cares. None of the people that haven't responded need to fly to our wedding. It's a 5 hour drive at most and one couple lives in our city.

I didn't mind declines, or even people who missed the deadline, I minded people who couldn't be bothered to answer messages following up.... especially the guy who asked specifically to be invited!

Or, the guy who had to be chased down for a reply, then no showed because (I'm not making this up) he said we would be having too much fun. ??? That's a problem?