In the situation you're describing, Happy Eyeballs would've kept spamming unnecessary packets across the internet from any framework/language. Python's (technically correct) usage of IPv6 forced someone to actually fix the problem (the misconfigured firewall or DNS).

The more of these half-solutions you make default, the more fragile and confusing networks become. Things like these are what I find so infuriating about "opinionated" frameworks like Go's standard library, because they'll happily apply patch jobs that'll probably mostly work most of the time as a default and leave you to reverse engineer the problem when the workaround eventually collapses.