I think there could be different things going on: (1) some people think they are helping by providing criticism. In my field a lot of people will review my work and give feedback, and it can feel like they are tearing it apart, but really it helps me find the holes so I can make it even better. So that could be some people's take - that they are "helping" by giving you critical feedback. OR (2) some people just like to take other people down a peg to make themselves feel better. And that "some" is actually "a lot" of people. A LOT of people feel bad about themselves when they see a friend or family member succeed, so they criticize that person to bring them back to their level and make themselves feel better about being mediocre or failing at one thing or another. They don't even really know they are doing it, and it's not so much that they mean to harm you - they are protecting their idea of themselves as successful by making you seem less successful. So, as in all things - their comments are really about them, not about you or your project.