Animals and humans don't have the same saliva so what works for them doesn't work for humans. I believe someone who feels the need to troll lacks self love and respect. Once they obtain this from therapy or wherever possible, they will no longer feel the need to engage in this behavior.
"A common belief is that saliva contained in the mouth has natural disinfectants, which leads people to believe it is beneficial to "lick their wounds". Researchers at the University of Florida at Gainesville have discovered a protein called nerve growth factor (NGF) in the saliva of mice. Wounds doused with NGF healed twice as fast as untreated and unlicked wounds; therefore, saliva can help to heal wounds in some species. NGF has not been found in human saliva. It has not been shown that human licking of wounds disinfects them."