Any system that is open to the public will (sadly) have to deal with bad actors.
85% of all email is spam[1]. But that's not a value judgment on the technology--Humanity can still get value from email.
Sturgeon's law says 90% of everything is crap. If you deal with other humans, you need a way to sift through that crap. In the case of email, that means use a spam filter. In the case of crypto, it means don't buy shitcoins.