People who charge fellow artists to take pictures of them like this https://www.flickr.com/photos/dgterryphoto/sets/72157648485194673/
are the ones pretending to be something they’re not.
As far as deleting your account/post. I’m not sure it’s possible. It could be possible, but since so many in the past have changed their account names to things like “fuck Off”, “delete me”, and the like and yet their posts remain… I’m guessing there’s no option for it. I once was successful at editing a post after the allotted time was up, but for the life of me I can’t remember how.
Im sorry that you didn’t take the time to realize how brutal and honest the critques usually are here. Maybe a forum that requires people to sandwich any negative between complimentary nicey nice bullshit would be more your speed? There are plenty forums like that out there.
My advice to you is in the future when you seek critisism of your work, be prepared mentally for it. You might find this article helpful/useful