that's exactly the point I was trying to make. along with the fact that if I give you some 32 character HEX string where one HEX symbol appears more than 2 times, you don't have anyway of knowing what caused that to come about - be it just a random happening or something that was caused by a bias towards that particular hex digit.
I'm still having a hard time comprehending your point. That if I give you a number you can't know if it has a certain bias?
that's a bit unrealistic to force someone to roll a dice around 600 times just to generate a single bitcoin private key.
First of all, it's not for a single private key; it can work as a seed, which can be later used to derive nearly infinite private keys. Secondly, you should absolutely force nobody do anything; especially regarding this matter. It's a process that concerns you, individually. Same as with using bitcoin.
While paranoid, I still prefer tossing a coin, or rolling a fair dice, than using an RNG from a computer I don't trust. In my case that I have two computers, one that I'm currently typing, and another I don't trust with all that software I've installed over time.
(I say paranoid, because I've never heard anything of "RNG exploitation")