If your government refuses to stop the flow of drugs into the US by addressing cartels don't be surprised if the US delivers weapons to said cartels so they can have some infighting going on.
If the mexican government would actually make work of dismantling the organized trade, there would be no incentive to deliver them weapons to shoot each other.
supply is never an issue, USA would supply poison to entire planet if the demand was there. blaming Mexico for the sickness of our society is very rich (but often repeated)
If the mexican government would actually make work of dismantling the organized trade, there would be no incentive to deliver them weapons to shoot each other.