When all is said and done the object of a game is to entertain and amuse those participating in its play. In my considerable experience with players, it is generally preferable to them to have a viable character of their choosing with which to adventure. Having a PC with a prime stat of 16 with which to begin play is a desirable thing for the majoprity of players, certainly the vast majority of new players.
When the D&D game was first created, state meant little. As it developed, stats became ever more important to the PCs success and survival.
In these regards I submut that the methods of determining PC stats in the UA work had nothing to do with munchkinism but rather to do with capturing and pleasing player participants. Munchkins miraculously rolled stats of 18, 17, 16, 15, 15, and 10, for Charisma and as proof the numbers were honestly generated, no matter what dice system was used to determine these ratings
Frankly, IMO the grousing about UA is just another gamers' exercise of their personal opinions of what is "right" and "wrong" in the RPGof their choice. That is something I fully understand, do on occasion myself (even in regards to what I have prevously written), and have no quarrel with. There is no accounting for or disputing of personal tastes.
It goes without saying that my own are impeccable, and all that disagree with them are just plain wrong
Gary