So I was reading this post and decided to make the tool described, as a userscript (I credit ChatGPT with doing most of the work, which went pretty quickly). To use it, install a compatible userscript browser extension such as https://violentmonkey.github.io/ , then press install on the linked page. Reddit comments should now have a 'copy-context' button that will put the comment chain in your clipboard. I made it for old.reddit so probably won't work with the redesign. Another limitation is that it will only work to copy what is on the current page, so if the comment chain is too deep it's not going to get all of it.

Any feedback is welcome. Also if someone who can read javascript wants to give it a once-over and confirm for people that it isn't malicious that would be cool too.