You're gonna have a lot of problems if they think these are personal attacks rather than actual criticism.

These kind of comments are pedestrian. I hear them every day and I listen to them. Growing a thick skin doesn't mean I'm ignoring all the comments but it means I don't take everything personally.

People rarely hate someone else's guts personally, especially on the Internet. They are simply passionate about what they believe in. Your job as a designer is to find out why they believe in what.

I'm glad you said you have no intention to work in design though, because you won't last a day in a design firm (or even art school) if you cannot even take these comments.