I think I understand what he's saying, and there are some point I can definitely see taking place in the church right now. When he speaks about not knowing the heart-motivation, he's right; The Bible tells us to avoid the appearance of evil, and I think that is difficult to do when you're audience isn't controllable.
I am no saint in this area certainly, any (honest) Christian will tell you they struggle to control their tongue (James 3 speaks a lot on this). I, personally, feel a conviction about my tongue and the words I intentionally use. I believe there is no situation where cussing produces good "fruit".
In this situation with POD, I just don't think it was using Godly wisdom to intentionally choose the words he did to convey his message. They have an opportunity, a platform, to speak to a great mass of people, and I believe the hope they were trying to present could have been done in a better manner. I understand their position behind it, and it sounds as though they don't have a real conviction regarding "cussing", so the argument is moot. They've even had these opportunities to explain their words, and share their heart on the matter, but I'm not sure it is just to throw Christians under the bus because they live by a different standard of holiness that POD does.