How/where someone "gravitates" is driven by social/economic/political forces. Your reasoning is based on an (incorrect) assumption that there is something intrinsic in the individuals who become gang members that drives them to be so independently of their socio-economic status. For this in fact to be the case, we would have to observe identical levels of criminality in all socio-economic groups at all times. What we see instead is that criminality levels are much higher in economically disadvantaged groups, and that such rates increase in times of economic downturn. The unavoidable conclusions, to the honest and objective observer, are that:

1) so-called "criminal" types would pursue "honest" professions given the opportunity and

2) so-called "upstanding citizens" would take up crime if denied alternatives; they don't do "crime" because they are in a social position that allows them to sieze resources legally

this of course is the major flaw in so-called "conservative" thinking, which advocates "individual responsibility". In fact, it's just a big cop-out (no pun intended) that allows the economically fortunate to deny collective responsibility.

Most of these gangs came out of places like Honduras, which have been economically marginalised purely so that American consumers can pay a few cents less for the shirts, sheets and towels that are produced by their sweatshops. Anyone who treats human life with that level of contempt doesn't have the right to complain about some gang evening up the score a little bit.