The gesture has multiple meanings. Here is an example: In Hinduism, the hand gesture is known as the "Apana yogic mudra". In Indian classical dance forms the hand gesture symbolises the Lion. In Buddhism it is seen as an apotropaic gesture very commonly used by Gautama Buddha as "Karana Mudra" which is synonymous with expulsion of demons and removal of obstacles like sickness or negative thoughts.
Not necessarily a bad thing.
https:// en.wikipedia.org/wiki/Sign_of_the_horns
The apotropaic usage of the sign can also be seen in Italy and in other Mediterranean cultures where, when confronted with unfortunate events, or simply when these events are mentioned, the sign of the horns may be given to ward off bad luck. It is also used traditionally to counter or ward off the "evil eye" (malocchio in Italian).