Two things, his dogmatism, and his unbending cconviction that he's right, even when he's proven wrong.
True.
In terms of self-education (and, for that matter, home education) the internet has certainly made research easier, and I'd broadly agree with your quantification of the quality of material being similar.
My problem is that we have a situation in the UK (and, IMHO, many other countries) where critical thinking skills aren't taught
until higher education, whereas if they were taught as part of standard (non-sixth form) secondary education, then people would be provided with the tools necessary to self-educate to their hearts' content.
I don't think it's at all pretentious to say that bulletin boards may, very broadly, act as educational sites, insofar as they often draw people into proximity with ideas and concepts that they might not usually come across. I know I've pretty much been an eternal student in terms of continually and actively seeking to add to the sum of my knowledge, and boards like Urban have sent me down intellectual avenues I might otherwise have not bothered exploring.
Vocational and technical training and self-education is, of course, another thing entirely. It's hard to self-educate when there's so little access to the building blocks of basic technical training nowadays.