Not necessarily. It's more like if the refs had a low enough threshold to call a foul during a normal defensive series for the Thunder, they'd be calling them all the time. So rather than OKC committing 60 fouls and the refs only calling 20 of them, the refs are in a situation where they'd have to either call 60 or only call 10.
I'm not saying that's what's happening here -- I haven't watched the Thunder at all outside of Spurs games for a while now. I'm just saying that's a way for both ideas to be true at the same time. Just like an umpire can establish a strike zone, the refs can establish a threshold of permitted physicality, and with both the conventional wisdom is it's discretionary but should be consistent for both teams. The issue, of course, is that it's not consistent for both teams, or for all 10 players, or for all 48 minutes. Too much of it is finesse and interpretation. Too many make up calls. Too much tolerance for complaining and flopping. The Lakers were embarrassing last night in how much they cried after every bit of contact (and SVG was horrendous for agreeing with them every time and then saying nothing about the Spurs). If that's how SGA is when he doesn't happen to get a call, I am not looking forward to the game on Saturday.