When many join Deviantart it is for showing their art and maybe gain some fame. Also many are to lazy to create a own website or portfolio. In the end when it comes to Deviantart you are going to come across people which spend most of their time attacking peoples art.
When you see somebody attacking your friends artworks, famous or not famous artist you shall follow these simple rules:
5 ways to become a better fellow Devianiart
1) Never flame somebody when gained critic, try to ask why they dislike the artwork, even that you added "no critic" option. They might just want to say an opinion. Try to stop other people from flaming that person. Just out of kindness.
2) Never ever just add something as a favorite, try to leave a comment if you can. Just to show you like that artwork all the way.
3) It does not just excist one type of art style, it excist many out there and none of them is wrong. Anatomy does not always follow all types of art. But try to get a own style do not just