http://jbr.me.uk/ranto/index.html
[1] ("NEW LANGUAGE? DON'T WANNA! WAAH!")
[2] ("The language I happen to know best also happens to be the easiest and best and most universal. Funny how that worked out, neh?")
This seems to be the biggest unanswerable criticism the Esperantists face:
"It looks like some sort of wind‐up‐toy Czech/Italian pidgin. And if there's one part of this world that doesn't need a local pidgin, it's Europe, which is not only the continent whose languages are best covered by online translation services, but also the home of the current de facto global lingua franca: English."