That's not really what's happening. My script is scraping the website, sending thousands of requests, so to a website operator it looks like a ddos attack. It may even have been cloudflare blocking the ip automatically. If he was blocking archiving, they would just block incoming requests from archive.today, which probably uses multiple IP addresses.
tl;dr They are blocking my scraping of the site, not the archiving. You can see all archived urls at
https://archive.today/https://hashtalk.org/* (notice how many are from the last hour? That's a script for you.)
Run them through a caching web-proxy. Apache/squid/etc on client-side, Opera's stuff on the server-side.