Think about how long it took you to create an "account" on Nostr (1 click?), then imagine automating that.

You can mint millions of "Accounts" in no time and have them all do whatever you want. Trying to remove them is a futile fight. Clients will find increasingly clever ways to only display probably-human content (they already are). Eventually global will just be raw botland.

Clients could also only display probably human followers. But trying to remove bot accounts will always be an exercise in futility. You could subscribe to the view that all relays should charge an initial fee, making spamming accounts unprofitable. My view is that throws the baby out with the bathwater.