We definitely want good critical comments here, so in that sense you're correct—but we don't want shallow internet putdowns. Those grow like weeds, choking out interesting conversation and eventually degrading the entire ecosystem.
Your phrase "express their true feelings" is interesting in this context. Shallow internet putdowns aren't true feelings. Often they're a kind of side-expression of someone's bad mood, frustration with life, or whatever—feelings which are actually about something entirely different than (e.g.) AR or holographics or whatever the topic at hand is. Those feelings get displaced into internet swipes because the latter are cheap, risk-free, and bring a slight temporary relief. But they're not "true feelings". If they were, they'd be much more interesting reading.
The GP comment actually included a great second paragraph saying something about what they'd really like to see, and that was interesting because it was rooted in genuine curiosity and enthusiasm. But there was no need to put down someone else's work for not being that.