I think it's more "the target audience for webp is people closer to and arguably less trained than my eyes and I can't see a difference" which is a pretty reasonable take. But tech people aren't typically the best communicators and so I'm not at all surprised it comes off crass.
mp3 is "worse" than flac but if you say it sounds bad I'll absolutely tell you you're wrong and to get off Hi-Fi
forums.
If your goal is to batch convert a wide variety of lossily-compressed source material at a significantly lower bitrate without obvious loss of fidelity, MP3 is not great.
That appears to be the author's specific complaint against WEBP, and seems fair.
mp3 is "worse" than flac but if you say it sounds bad I'll absolutely tell you you're wrong and to get off Hi-Fi forums.