I'm mostly curious why anyone would bother with doing attacks like this to some random individuals personal blog, was it one person or multiple people? What was the motivation? Is it just bots crawling the internet to spread hate?

A sad state of affairs, but certainly seems like having a strictly moderated comment section is a better option for a site like this.

Bored kids. Bots. And scammers/spammers. On the scale of the internet, there are a lot of all of these.

Same reason any blank wall in a city will soon be covered in graffiti.