That just shows a lack of knowledge of statistics. If you don't believe in those stats then you don't believe in pretty much any stat. Cause they're all subjective in the most insane way. UZR doesn't claim to be perfect, but if UZR says Johnson is a bad defender, DRS says Johnson is a bad defender, then odds are he's a bad defender.
Let me just throw this out there. The extremes. The top 10 in UZR and the top 10 in Plus minus last 5 years, for DRS it's Brendan Ryan, Longoria, Beltre, Bourn, Pedroia, Heyward, Kinsler, Jackson, Gordon, Adrian Gonzalez. For UZR Longoria, Bourn, Heyward, Ryan, Beltre, Petroia, utley, Adrian Gonzalez, Hardy, Ichiro. Basically there are 2 outliers in the top 10. For the same thing with the bottom 10 in DRS Kemp, Weeks, Ibanez, Aramis, Uggla, Jeter, Fielder, SOriano Reyes, Howard for UZR Kemp, Fowler, Asdrubal Cabrera, Adam Jones, Ibanez, Uggla, Ethier, Markakis, Braun, Dye
So there's some arguements between the 2 but in general I think most would agree that guys like Kemp, Uggla, and Ibanez are all horrible defenders.