Constructive criticism is what helps creative people evolve. You're right, you can absolutely come in here and just be a dick about an artist's freely public, carefully designed, creative project that is already a super niche, difficult genre that they've worked hard on, say "Eww, gross" and just leave.
The alternative however, is to maybe acknowledge what it actually was you didn't like, and to give the creator some food for thought, maybe some insight they might not have. There's a saying "Say something nice or don't say anything." and there's a reason that exists, it keeps people from just getting torn down over and over with no incentive to improve.
I'm not saying you're not allowed to dislike, or even hate it, totally your opinion. But a little clarification on what was that looked so simple about it would make a big difference for the artist, the other players, even you.