I've bought pretty expensive equipment, tube amplifier, many fancy headphones, optical DACs. A library full of FLAC files. I even purchased a $500 portable DAP. I've never been able to reliably tell a difference between FLAC and 320k MP3 files. At this point, it really doesn't concern me anymore either, but I at least like to see my fancy tube amp light up.
I will say, though, $300 seems to be the sweet-spot for headphones for me.
For this specifically, "Traitorous Critic Fallacy". More broadly, an Ad Hominem argument.