'GTA V' -- Get a Life Animal Org. ... It's an Adult Game!

The "Grand Theft Auto V" boycott being called for by an animal rights org. is a molotov cocktail full of crap -- according to sources directly connected to the game ... who add the group is using GTA for shameless publicity.

Our GTA sources tell us game makers are calling BS on In Defense of Animals' attack on GTA -- saying the game does NOT push "institutionalized" animal violence on kids ... because it's not made for kids.

One source points out the game has a mature audiences only label, and kids under 17 can't buy it ... so there's no harm in showing adult situations to grown ups.

"It's a fake world with exaggerated real world problems" the source adds. "People shoot animals in real life, why should that be hidden from an adult video game?!"