That doesn't mean laziness. Consistency is a big part of talent. Analogizing back to offense, we've often seen players who can look like Kobe Bryant for a night, once every so often. We don't (usually) say, "See? He can be as good as Bryant when locked in, he's just lazy." We understand that a big part of what makes Kobe better is that he can play at that level consistently, while lesser players can only reach that level occasionally. I mean, sometimes people make the same mistake (IMO) on offense--Rasheed Wallace looking incredible at times made some people say that he was as talented as Garnett or Duncan, he was just lazy. I think most rational observers understood that Wallace, while a fine player, was not as talented as those two guys. He was generally very good, occasionally great. If he were more talented, he could have been great as often as Garnett or Duncan.
Even not-so-great, not-so-aware defenders can have nights where everything's clicking. Bad team offenses have nights where everything's clicking and they look great. That doesn't mean that that's their true level if they just tried harder. It means that at their very best, when everything is going right, they can look good. But their true level is a lot lower, it's where their averages end up. Is it possible that this is a great defensive roster that simply doesn't care enough? Anything's possible--I just think that's much, much less likely than that they have two strongly defensively deficient guards, a (small) shooting guard playing out of position and I don't know what's happened to Covington. He's always cared about defense in his career, so I don't think not caring is his problem.