I think grow thicker skin is absolutely vital advice for creators, or any job where at, bare minimum, you frequently have to work with an editor. Being a creator means people are going to be critical of your work. I'm not even talking just about fans, before your work ever hits public eyes, it's going to scrutinized and flaws/issues are going to be pointed out. Sometimes these aren't even entirely negative, it might be something like "This was really interesting, can we expand on this more," style comments. Hell, I think this is good advice even if you aren't creating content for entertainment. If you're too thin-skinned, you're going to be buried under criticism and, even worse, start holding a grudge and becoming spiteful to the people who are editing you. It's why a lot of "big" creators sometimes have works that just flop and don't match their previous quality. They become so prominent they're either able to basically do their own solo projects with no oversight, or everyone just pushes through whatever they say because of the previous success. Hearing about what you do poorly is just as important as hearing what you do successfully.