The thrust of the argument isn't wrong but I think everyone figured that out back in 2008 because its fairly obvious, regardless of your personal enjoyment of any or all of them, that Fallout 3 and Fallout 1/2 are not the same type of game and there's at least of couple of missteps in there when the guy starts trying too hard.
If I hear the "you can purify radioactive water with dirt" line one more time as a serious criticism I'm going to throw a vat of liquid virus at whoever says it. The setting has always been rife with scientific nonsense. If there is a problem with the irradiated nature of the Capital Wasteland and the way it is dealt with (and I would fully agree there is) it is not the fact that in the real world it wouldn't work that way.