Shamus Answers Your Fallout 4 Questions

[sXeth]

You'd also need a pretty decent level of Fallout lore to be aware that Super Mutants should not be in the Commonwealth though.

Fallout 3 does kind of heavily cover the FEV thing in a non-optional quest. And adds a second instance in the Lore of Vault-Tec running FEV eperiments in Vaults, which prettymuch means any given Vault could be creating Super Mutants. If they'd left it totally unexplained I would've just assumed some Vault nearby or now-buried was their origin point.

 

[pookie101]

as others have already pointed out it is possible to ask questions about things but that said its obviously really easy to miss as well