What is a "junk" request? Is it hammering an expensive endpoint 5000 times per second, or just somebody using your website in a way you don't like? I've also been on both sides of it (on-call at 3am getting dos'd is no fun), but I think the danger here is that we've gotten to a point where a new google can't realistically be created.
The thing is that these tools are generally used to further entrench power that monopolies, duopolies, and cartels already have. Example: I've built an app that compares grocery prices as you make a shopping list, and you would not believe the extent that grocers go to to make price comparison difficult. This thing doesn't make thousands or even hundreds of requests - maybe a few dozen over the course of a day. What I thought would be a quick little project has turned out to be wildly adversarial. But now spite driven development is a factor so I will press on.
It will always be a cat and mouse game, but we're at a point where the cat has a 46 billion dollar market cap and handles a huge portion of traffic on the internet.