Is it mean to call other languages "gibberish"?

I like to say, "if I don't understand it, it's gibberish". I am just kidding of course, but would that offend you if you heard someone jokingly saying that

This page is a permanent link to the reply below and its nested replies. See all post replies »

DoubleRings · 51-55, F

It’s very egocentric. Like when Americans would come over here to Canada and call our currency “play money” or “monopoly dollars” (the bills are coloured). I would kindly inform them that’s real money but if they wanted foreign (US) currency they’d have to visit an exchange centre.