Blocked shots do not equal good defense.
Dwight gets totally lost on defensive assignments and will sell out his assignment to go for a highlight block. Much like Whiteside currently and Josh Smith before him. Howard has zero interest in learning how to actually play defense on his man. He'd rather go for empty stats.
Al Horford went for 30/14 and 22/9 on him last season. The same Al Horford that people here say can't play inside or rebound.