I get “spam” from sites where people registered using my email address. Spam is “Unsolicited Commercial Email.” Your example is not spam. It’s just a mistaken alert caused by a third party that you most likely won’t see again from Cloudflare.
Agreed. This is not “spam” from Cloudflare. Emails like this would most likely come from someone posing as Cloudflare (usually called “phishing”) or if someone is trying to use your email address. Not something we just send out to people who don’t use us.
If you have never used Cloudflare you should just be able to ignore. If you know (or think you might) have a Cloudflare account, an email like this should prompt you to contact support ASAP.