There are several long threads addressing all of this on this forum. Here are a couple of them:
http://forum.honeyflow.com/t/how-do-i-answer-this-criticism-concern-about-the-flow-hive/1206?u=dawn_sd
http://forum.honeyflow.com/t/how-i-explain-my-flow-purchase/6502?u=dawn_sd
The long and short of it as I see it is that there will always be resistance to new ideas. The traditionalists feel threatened, so they try to discredit the innovation. The plastic is BPA-free (not polypropylene) and the same formula used for baby milk bottles. I doubt it off-gasses. Plastic has been used in hives for decades (plastic foundation and frames), and while bees may be reluctant to use it the first time, once they have waxed it and put footprint pheromones in it, they use it willingly. Flow honey should always be harvested from capped frames too - that is just not an issue. The Flow frames are just a different way of harvesting, not of beekeeping. You still have to look after the bees the way you would in a traditional hive.
There is a learning curve with using the Flow frames, and some tricks and skills are needed to harvest gently and efficiently, but I think it is a great concept and not trickery or battery farming of bees.
Generally I don’t discuss the Flow hive with most traditional beekeepers any more. I will just be happy to sell my pure, unprocessed honey, and perhaps win the occasional prize for its outstanding quality! 