Earlier quoted context omitted.
To be fair, he directed people to a >500 page book on the subject as a good introduction to some of these ideas. Do you expect him to effectively summarize a massive text in a single HN comment?
Is three sentences asking too much?
For example, instead of telling me to read a 500 page book, you can say "the Big Bang is this really crazy but suprisingly plausible theory that our universe just suddenly exploded from nothing into this really hot and dense and chaotic realm, and now everything is expanding and cooling down and getting farther apart but also clumping together because of gravity. Check it out!"
Becuase at least then you can say "oh wow, why is it clumping together? how do we know gravity is a thing?"