Best cure for that is "treat others as you would want yourself to be treated". In this case I would really appreciate it if someone told me that my idea wasn't novel at all, sucked or that I was charging exorbitant fees for some minor improvement of my productivity.
A lot of times in life, kindness doesn't look like kindness.
"In this case I would really appreciate it if someone told me that my idea wasn't novel at all, sucked or that I was charging exorbitant fees for some minor improvement of my productivity."
Ok, but if the reason you think something "sucks" is because of an uncommon opinion that you hold, like a good UI isn't important or worth paying extra for, then your comment isn't very helpful to the creator. It says much more about you than the product.
Similarly, most people in tech/knowledge work would not consider $15 per month for software that makes them more productive to be "exorbitant", and I think we all know that. If you feel that way, fine, but it's not relevant to the discussion.
"Someone told me my idea sucked" is not in and of itself any more of a useful signal than "someone told me my idea is brilliant"; one person's opinion is, well, one person's opinion. Who that person is makes a difference. In the case of SigmaOS here, the "(YC S21)" suggests that they've had at least one very positive signal: YCombinator accepted them. "The most famous seed funding group in the tech world likes us enough to work with us" is probably more of a meaningful signal than "SnarkyTechGuy1337 left us a cutting comment on Hacker News".
A lot of times in life, kindness doesn't look like kindness.