Its in there instinct to still go to the city to hold and the outsiders captured and changed to Super mutants either followed the older ones or would go out in the wasteland.From what ive seen they mainly use hunting rifle mini gun or missile launcher. but if there intelligence could reason there weapons are more deadly and advanced.

I had wrote multiple paragraphs but for some reasons my stupid laptop built in mouse highlighted everything cause it felt my thumb brisk and my index finger tapped some button and bye bye work. I had talked more about how the Super mutant vault was U.S. Goverment owned and the tests also there vault has another exit/enterance. Also the intelligent Super mutants and how these mutant tests were going on pre war since in new vegas you learn the goverment used the mutants as weapons and advancing them up with nightingale powers. Also these could have been the U.S. Goverment seeing there falling apart so they'll have everyother person die to.And how in the earlier fallouts mutants had total control of a vault and would talk to you but still had the savage in them like the supermutants on the radio tower moutain in new vegas. (these are all theories i have come up with looking at from what i have seen in the games so far)

Eh, they want more "green stuff", they figured that DC looked like an important place so they're rummaging through the ruins looking for it.

Whats this "green stuff"? do you mean the stuff that changes them into mutants and say your right then they could be wanting to make the D.C. Ruins there new "breeding grown".

We don't know exactly what's going on in their skulls; these guys tend to be as dumb as the "dumb-dumbs" you see in New Vegas. If you notice on Black Mountain Radio, it was fixed up by 1st-gen Mutants and run by a Nightkin. Both are of human-level baseline intellegence (at least, although Nightkin tend to suffer from multiple mental illnesses, affecting their apparant IQ.) The 2nd Generation Mutants (Dumb-dumbs) aren't much better than for use as cannon-fodder.

What we do know is that they want more "Green Stuff," the FEV (Forced Evolutionary Virus.) It's what they use to make more of them. West Coast Super Mutants are dunked, East Coast are exposed via the air; this difference is the reason why the East Coast super mutants are so dumb.

Anyway, they might have somehow linked "Green Stuff" to radiation. Since DC has some of the highest concentrations of radiation in the CW, it makes sense for them to go there to try and find it and bring it back to Vault 83. Any bigger plan or more complicatied rationale is beyond the mental capacity of DC's Super Mutant populaton. Sure, Fawkes and Uncle Leo can make sophisticated plans, but they're an exception, and mutants like them are effectively exiled by the Super Mutant population (if not killed first.)