The good/bad pine debate seems to be a lot like whether or not wire for rabbits is good or bad.
I was reading up on pine for rats a while ago. Kiln-dried pine, which is what most pine bedding is I think, is actually fairly safe because it's been baked and the moisture and harmful stuff evaporated out of it. However, it does seem that pine can affect the liver of rats just enough that they can't process medications correctly, and that seems to be the only real reason it's not used on lab rats and probably what got it deemed universally unfit. Rats have sensitive respiratory systems too and REALLY live down in the stuff, yet there are breeders who've used kiln-dried pine in their racks without RI issues for decades.