It's fair to mention that he is well known, though in fact I'm one of the old guard that remembers when he had a higher profile.
But, as with a new Paul Graham essay, surely we can critique the blog post on its merits instead of falling back on an assessment based on some kind of appeal to authority/"expertise by association". Philip Greenspan doesn't need to be treated with kid gloves as if he was the pope.
John Ousterhout made comments that touch on some similar (though not identical) distinctions in programming practices. That was years ago, and he was then a much more credible figure in software than Greenspun. All the same, his essay was heavily criticised. That's what serious intellectual discussion should involve.
There is nothing myopic about his perspective.