It does no such thing. It only brings a visual opinion of a soldier. You shouldn't judge a book by its cover.
Tattoos have no bearing on a soldiers attitude to his duty. People can easily be gang members or criminals without tattoos.
BTW, I got mine while in Basic Training.
I know I shouldn't but I still do. If I see a gold toothed 17 year old festooned with tatoos, my first inclination is not to think what a fine display of body art.