>>7-10
It definitely is disambiguation in a purely technical sense.
Consider a hyperlink residing on the page http://4-ch.net/dqn/foo.html. The following hrefs will all direct your browser to the neighbouring file bar.html:
If // were not mandated to be at the beginning of an absolute URL, cases 1 and 3 are still unambiguous but cases 2 and 4 are hosed. Your browser would have to decide whether or not to visit these pages instead:
2. http://4-ch.net/dqn/4-ch.net/dqn/bar.html
4. http://bar.html
This is why the // is necessary. Not because TBL has a cult of personality.
I hope >>8 and >>9 are ashamed of themselves for attempting to discredit a set of incredibly well thought out communication standards made by a number of incredibly clever people on the basis of a pair of forward slashes. Yes, a lot of the Internet runs on ad-hoc trying shit out, but 99% of this ad-hoc mess is due to people not following standards. (Microsoft, PHP developers of the 90s, Chrome-using web developers of the present, I'm looking at you.)