If it's easy to criticize it's also easy do dismiss. Learning a new language is a lot of work, if said language has a tiny amount of speakers and there are some obvious (albeit subjective) flaws that you're unhappy with, why would you bother with it?

Invented languages are like social networks, it's all about reaching that critical mass where the network effect is self-sustaining. Getting there is extremely hard however, especially if, like the parent points out, it's incredibly difficult to actually make a language "objectively" superior to the hundreds of existing languages which already have millions of speakers.