Earlier quoted context omitted.
This question turned up a few hours ago over here [0]. Apparently some ISPs are perversely hostile to peering. [0] https://news.ycombinator.com/item?id=22627764
They are incentivized to attempt to charge for paid peering. It’s not that perverse, unless you like the internet going fast more than you like money.
Likely some ISPs see themselves as offering more valuable traffic than their competitors striving to peer.