Not to sound rude

It makes sense to me not to sound rude when making comments, but you can never know for sure how someone will take things, because everyone thinks differently. I guess that all you can do is just to say it in the best way you can think of and hope that the writer won't take it the wrong way. The writer should be open to ideas and I think that to do that you have to not get offended easily by things that people say. Having an open mind though doesn't mean that you have to agree with every little piece of feedback you receive, but you can still keep it in mind when you revise your paper.