That is because it is his opinion. Most people that complain about something, don't fully understand it. I have 35 years of experience, and see nothing wrong with them.
I'm convinced a person like Walter Bright knows a thing or two about software development in general and creating and implementing programming languages in particular.
None of us is as smart as all of us.
I think it's fair enough to do the former, even if i don't agree with them, and likely won't change my mind in this case.
The man makes his living designing and implementing programming languages.
He expressed his opinion on the subject of designing and implementing languages.
Enough with this petty anti-intellectualism. If you have nothing of value to add to the discussion please remain silent. Your ignorance is not comparable to someone else's knowledge and experience. Expressing envy and pettiness regarding other people's knowledge, skill, and professional accomplishments does not pass off as a technical argument. It just sounds petty.