Would a modicum of caching in GitHub Actions libraries not make this problem go away for all hosts in this category?
I think a quite reasonable expectation from GitHub would be to have an all-of-GitHub-wide rate limit that CI can use for requests to any given site, and have jobs fail/delay if GitHub has exceeded that, and expect sites to explicitly opt in if they're fine with more than that rate. Would of course very much suck for GitHub CI users that want to pull from sites not opted in, but at least GitHub would stop offering free DDoS services.
Are you saying it's not an ISP's problem that spammers are using their product in a legitimate manner, but instead it's up to the recipients to build their own spam fighting resources? Yes, that turned out wonderfully.
Anyway, I don't think your example aligns with the argument you think you're making: https://www.fcc.gov/enforcement/areas/unwanted-communication...
Yes, phone companies definitely can be liable for bulk targeting by their users.
The headline and title are saying GitHub DDoSed a crucial open source site, so the metaphor is definitely valid. I did not compare DDoS to death threats, I compared the fact that it is being said that GitHub DDoSed the open source site and did a thought experiment to see what happens if something similar was said about the phone companies.
The problem is within GH's network, a 90s ISP would have blocked spammy users, GH should at least operate like an ISP if random stuff can execute and reach the 'net.