Is it worth blocking over 1 Billion potential customers to slow(they could still find a way around) something that wasn't causing any real harm anyway?
Strange stuff it is, but would need some deeper analysis to figure out what they're trying to accomplish.
Could be some kind of "smart" bot that tries to sign up to any site it finds, to do spamming or whatever. I found this:
https://www.dlitz.net/blog/2011/10/m...mmon-losenord/ and it looks alot that it's the same guy/bot there too.