"Nefarious" is a strong word. Courts have repeatedly ruled that scraping data that is otherwise available publicly is legal. You may not personally agree with the ethics, but there are a lot of people who do.
At least in the United States, sounds like the jury is still out on the legality: https://www.reuters.com/technology/us-supreme-court-revives-..., but my perspective was more from an ethics standpoint anyway.
That's not what this tool does though. It allows you to distribute your scraping to a layer of proxies. So, the only difference is whether there is an intent to do harm to the target or merely collect data... which could be a form of doing harm as well?
There's definetly an argument that dangerous tools should be regulated to varying degrees. If we're arguing regulations in this specific area you'd probably also be balancing it with regulations that sites can't close an account for reasonable rate automated access and that public research can have higher rates so long as they're not crippling.
I wouldn’t regulate this but If you’re introducing regulations, why not just require the source to deliver the data in a neatly packaged format? The necessity for scraping and the potential for DDOS and potentially nefarious behavior basically goes away.
I think that means the jury is still out, as you mentioned, but it's leaning towards scraping being legal as long as the data is publicly available. IANAL