Read through it. Web of trust is a score. You would get 0 at iniciation of the npub. With every follow, that follows you back, you get a plus. And with every follow of a person you get blocked you will get minus. When I would say I only see posts of People above 3 every bot would at least to lounch three new npubs to have one personalized attack.

I would not want to spend significant batterylive to send notes, likes and posts. When it would be somewhere around 0.2 seconds of smartphone power, yes. But you have to think of all the majority of people that have old smartphones to build this up without rejecting poorer users.