You can see for yourself why he was banned: https://news.ycombinator.com/item?id=10017538

True, but it's more b/c his criticism of VC and PG specifically has a Captain Ahab level of intensity and persistence, which can get in the way of discussing, well, anything else.

Exactly, which is why I made the connection.

Still, the "single-issue commenter", as exemplified by both of them, can be valuable to a good community. @michaelochurch's writings have definitely shaped my thoughts, so kudos for him, and, if I were in the position to use it, @graycat's bibliographies would be rewarding to mine (unless his knowledge is outdated, as @barrkel suggests). Yet I can't help but get the impression that the single-issue commenter is very prone to overexposing themself, especially if a large proportion of their comments are multi-thousand word diatribes that recycle most of the same themes. Not to mention, people readily pattern-match prolix commenters to complete crackpots, even though both those users seem to be above that level. My impression is that single-issue commenters would be best served by posting a lot for a year or so, followed by some time to lie low -- if their contributions to the discussion around their issue are really valuable, their posts should stay in moderate circulation as other users refer to them in later discussion.