It's also being dismissive of real problems people face. It's an excuse to not address problems here and now because bigger problems exist elsewhere. But you aren't going to do a goddamn thing about those issues, so this implied triage is a lie. It's just a way of trying to act morally superior while lacking empathy.

The whole first world problem concept implies everyone has it easy in first world countries. As though we don't have poverty, mental health issues, crime, corruption, police brutality, abusive families, disease, loss of loved ones, and so on. There's no shortage of problems anywhere.

And you know what, fuck this attitude of turning suffering into competition and mocking people for being bothered by things that aren't life altering. There's nothing wrong with a healthy expression of emotion when you are disappointed or irritated, as long as you aren't taking it out on others. But being a snarky asshole to someone and judging them for having a bad day isn't helping.

If you see someone frowning and your instinct is to tear them down rather than cheer them up, maybe you should take a good look at yourself and figure out what your fucking problem is.