When Mavs fans were touting their big win streak, Spurs fans would mention the (low) quality of opponents and get bashed.
Bottom line is that you can only play the teams that are on the schedule and the Spurs are playing good basketball right now as they head into the stretch run toward the playoffs - whoever the teams are that they are beating. I don't care about what the Spurs record was agains the elite teams of the West early in the season - the Spurs D sucked early in the season.
I only care about what is happening right now. And right now - the Spurs are playing very good basektball.