The OP put those addresses on that web page, and only on that web page. Some addresses received spam.

Edit: that’s not to deny that big data leaks are a serious problem

I'm not denying that it happens. I'm saying that it not the classical way to spam people nowadays.

It's obvious to any non native english speaker, when you have a spam in english, it is because they toke the email from the web. When it's in you native language, it's usually from a data breach.

I'm vastly more spammed by the later. I can confirm it with unique email addresses of the "+" form (but not with the + character).

Also when I'm spammed in english, it's for Web3 crypto stuff and from a data breach it's a phishing attempt.