My thought process on collectibles is... and its an opinion which I know some people will freak out about... they are something to collect. Shocker. You collect something to be proud of your collection, whether you show that pride publicly or it fulfills something for yourself, each person is different. I don't think anyone outwardly collects or gets collectibles to "brag" or "show off" because that person would be shunned and no one would sell them anything lol.
If you think someone is "showing off" and "bragging" because they display nice collectibles or get defensive because someone misinterpreted your sarcasm, you need to think about your own role in that situation and take responsibility. you can't just assume someone else's motive or change someone else's mind, but you can be more cognizant of what you put out in the future and big enough to take fault in your own bad assumptions or poor joke. To do otherwise is just an excuse.
I'd be mighty upset if someone judged me based on how i show off nicely coordinated feathers and candies. I'd also be mature enough to apologize if someone got upset because I made a joke that someone got offended by, which I do a lot because I have a weird sense of humor around my irl friends.