I have a few servers exposed on IP addresses, but they are not meant for public access. You have no authorization for 'messing' with this site: what you deem playing around, might be hacking.
You may also hit a government or military IP address, known or unknown. If you mess around with them, you may receive some unfriendly visits from men in black.
You DO NOT have my authorization to block or restrict my ability to mess with other hosts. Doing so may be a violation of my terms of service, and interference in interstate commerce.
Then, I think, you need to implement "reasonable measures" to secure them. Otherwise it's like putting your stuff out by the curb.
[21/Jun/2021:19:07:19 +0000] "GET / HTTP/1.1" 301 169 "-" "Expanse, a Palo Alto Networks company, searches across
the global IPv4 space multiple times per day to identify customers' presences on the Internet. If you would like to be excluded from our scans, please send IP addresses/domains to: scaninfo@paloaltonetworks.com"
I still get so. many. random people entering passwords and trying to break in. They don't look like a wordlist or automated bots, they're literally people guessing.
Just because you see a username and password screen after you nmap this public IP, doesn't give you the right to start trying to hack it.
You ought not try random usernames/passwords on someone's public server, I agree. But if you expose a public server that lets someone type a username/password, you had best be ready for someone to guess values.