Oh, but Alan said "Garcha", not "El Garcha"... that's different. It's not talking about a person. It's talking about an action, ha, ha XD
Uhm... in Argentine Spanish, "garcha" as a noun may mean one of two things. Either that the guy's taking many women to bed very often or that he's a scammer, somebody that can't be trusted. It is, of course, a very informal word and doesn't sound good, ha, ha. If it weren't his nickname, it'd definitely be offensive.
El Garcha seems like an argentine "enganche" (the argentine equivalent of trequartista), Gabriel "El Garcha" Giménez. This fake player started on Chacarita and signed with Rosario Central in 2015. Brazilian side Grêmio is looking for him.
El Garcha ... seems like some kind of narcos nickname.