Um...If modeling is considered a form of artwork...and the artist, be it a he or she is critical of other peoples work in that field, then how/why would they themselves misconstrue a comment about there art and take it personally..
I think that it is a bit more involved than this. I think it has to do with delivery. If I post a design that I worked hard on and someone posts "Wow, this sucks, go kill yourself", I'm going to be more than a little miffed. I'm not 'taking it personally' per say, but I'm still angry at the fact that they just spammed with inarticulate hate.
Now if I post the same design and someone posts "Hey, It doesn't really do anything for me. This is probably because the engine design looks tacked on, it doesn't really add to the shape." or even just an honest, but polite "Don't mean to be rude, but it doesn't get me excited." I'm not angry in either case. The first one gives some honest C&C, the second one is stating an opinion politely. I'm okay with people have opinions, and I'm okay with people sharing them. I'm NOT okay with people doing it rudely or unfairly.
Now, in the matter of the age-old "is modeling art?" question. I find the answer to be "sometimes". Art, to me, is the creation of a thing to evoke a response - be it intellectual or emotional. Most models, especially those you find on here, are more Design than they are Art. Design, to me, isn't about provoking a response, so much as they are a creation of an aesthetic. Now, granted, usually there is some overlap, and usually you need an element of design to hone-in on the reaction you want to provoke with your art. Furthermore, as art is very individualized, A good starship design can provoke an intellectual response from me - getting the gears turning as to what this would be like in-universe, rendering it art in my eyes.
Architecture is a good example of more-design-than-art, but a well written novel is more-art-than-design.
And of course, this is all just my thinking on the matter
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