They had played in Cleveland the night before, and I think that explains a lot of what we saw. But even still, that was a sluggish effort, and that's being diplomatic.
Keep in mind that this team is one of the oldest on the league and has virtually no above average defenders besides Lebron. Iman Shumpert being injured last night didn't help matters. Jae Crowder's defense has been below his standards all year. But no matter what happens, this team is going to be bad defensively.