That's the very point of a bdfl : it assumes he knows better than others. Debating is for insight and cortesy, not mandatory.
I think it's not that he knows better, it's that there can be a single, coherent, consistent design consciousness.
A BFDL can create an effective process of evolution rather than some of the more egregious open-mob process failures that are prevalent in open source.
In Python land, there is this saying "we are all adults here".
Being an adult also means avoiding creating needless drama.
One contrast:
You have some people who in business and want to do keep an old code base working forever.
You have some people who have no business experience and have no idea what a bottom line is, but might need a feature for a critical open source project that many others will use.
This analogy does not work in software.
I agree with the idea you should give power only to people that don't want it.
I think guido was the right person in power.
You can do something that people disagree with, even something that you think is the best for them, and still be benevolent.