What's being done about the madressas
(Islamic schools) were these people are receiving terrorist indoctrination
and the mullahs who are running them? The only way this reservoir can be
emptied is by turning it off at the source.

The sources are multiple, not singular, and not centralized. Therein lies part of the problem.

Turning off the source involves: following the money (already being pursued); tracing the political connections to stated enemies of the US (already being pursued), and to American "allies" (already being pursued, sorta kinda); and improving life in nations in which such fundamentalists have enough of a pool of the disaffected from which to recruit young men who have literally nothing to lose (current pursuit involves military occupation).

The trickiest part will be dividing fundamentalist religious groups in general from those whose teachings advocate and organize their followers to commit violence. As Americans, one of the cornerstones of our culture is religious tolerance. We can't be true to that and go around shutting down houses of worship because they are fundamentalist houses of worship. Some proof of conspiracy to commit criminal acts must be found in each and every case. Otherwise we betray our own principles. If that happens, we have won the battle and lost the war anyway, if one believes that the primary struggle is cultural rather than statist.

Fundamentalism is a separate but related threat, in my opinion, an opinion the Southern Baptists may not share with me. ;) Fundamentalism as a theology can be integrated or marginalized in other ways, and certainly not by armed suppression. Armed suppression only tends to make martyrs of the religious, sort-of like printing recruitment posters with human blood. The thought that one can commit any sin and be welcomed into Paradise anyway if washed in the blood of martyrdom is an excellent draw for fanatical believers.

Regards--
Mary Anne