As opposed to using C, Rust, or something else (Jon eventually made Jai but Casey still uses C++). Obviously they don't outright hate it.
It just seems to be wholesale aggravation so they want to reject things without a sound reason.
If someone asked me why I avoid inheritance I would go on a well thought through rant that connects real problems to the pragmatic reality of what that feature brings.
Yet if my job requires to use C or Go, I like my paychecks, have bills to pay and being proud doesn't pay bills.
Same thing with them, having to use C++ at work, doesn't mean they are big fans of it, indeed the very reason Jai exists is for Jonathan Blow never to use C++ again on his projects.