I think the original statement was implicitly about using the language to build large complex systems in industry, not just about "using" the language which I agree would be kind of silly - who would work on a language they don't use in
some way? But I always had the impression that most language designers were academics, e.g Alan Kay, Stroustrup, or professional programmers building what were initially 'hobby' languages (Ruby, python) rather than building something they would use in production in industry.
Standards must be low if that's now "deification" :)