Why don't you just unsubscribe from Change.org emails so you don't get them?

I did, but they still keep coming. Why won't they go into my "Junk" folder?

I did, but they still keep coming. Why won't they go into my "Junk" folder?

probably because they are not junk, simply unwanted. I would assume the newsletter/s you are subscribed to at change org would be set through your user profile on that web site. Not through clicking an unsubscribe link (as I am not a member I can not say definitively how the site works, but this sounds like a subscription issue on a web site, not a Thunderbird problem)

You could always use a filter to block the email f you can not manage to navigate the unsubscribe process. https://support.mozilla.org/en-US/kb/blocking-sender