For the same reason the Harley Bike Riders get tattoos -- to demonstrate their support and loyalty for the product, to attract people of like mind, and to make a statement about themselves. read more
Thirdly, if your tattoo is sub-standard, the makers of Monster Energy (I think it's a subsidiary of the Coca-Cola corporation) will in no way agree to pay for a shonky tattoo, as it reflects on them poorly with a douchey tattoo baring their motif being flaunted. read more