You “noted” it, but you did not provide any actual examples of it. You just posted a list of topics, and the fact that he does post in great detail on a wide range of topics does not imply that he must therefore be ignorant of some of them.
I didn’t follow the relevant thread, but this comment is utterly moronic. You are entitled to you own opinions, but you are not entitled to your own facts.
In a thread about whether Taylor Swift is a greater genius than Mozart, everyone should offer their opinions and arguments with equal vigor and assertiveness. (Although anyone who denies it is clearly a fool.)
But in a technical thread about (say) mathematics or physics, of course ignorant guesswork is not on an equal footing with contributions from people with technical expertise. That does not imply that people without expertise are are unwelcome to participate. Of course they are - but the appropriate way would surely be to read and ask questions and participate by learning from those who are gracious enough to share their expert knowledge.