The phase 2 diet is fine. The phase 1 diet is tough, but it’s short-term and you can still eat kefir, buckwheat, eggs, oil and some meat, as well as all the vegetables. To say it’s dangerous is speaking more with your taste buds than any sort of scientific reasoning. I don’t recall seeing anything that tells you how much you can eat either.
The phase 1 diet is potentially dangerous in the hands of people who aren’t balancing their meals or listening to their body. Just because some goon collapses after starving himself doesn’t mean people who have some sense are going to kill themselves, nor does it mean we should start eating potatoes and mangos. Christian’s experience probably has more to do with the cleanse, though it’s hard to tell with so little information within all the bitching.
Ultimately, it’s just a suggested protocol. It’s up to you if you choose to follow it. If you want to add additional foods, it’s your decision, but you can’t blame anyone if it slows or halts your progress. I’m sure there are people who can recover while eating additional foods (the list is still a work in progress), so maybe taking a bit of initiative would be a better idea than trying to force baseless opinions on people who’re doing fine with the protocol.