You're assuming the creator of the spider trap also put in CSRF protections. However, if you read the article, you'll see that it is only a link, with no CSRF protection at all. Therefore, it is quite true that spamming research mailing lists could lock a lot of people out. In fact, since this spider trap is triggered on a GET request, you would just need to embed the link as an image, script, or stylesheet and get the target to visit a page.

You could even embed the URL as an image in the email, and if images are enabled, it would trigger a GET request.