Because the law deals with intent. The intent for a 12 year old skiddie with a ddos box is to harm someone else's internet. the intent of big scrapers is to collect data. if you want to make the latter illegal then vote for that instead of loading it with the normative baggage of the former.

It's the same problem as why Occupy Wallstreet fell apart: bunch of losers who don't understand the system screech about the system. because they don't understand it, they can't offer any meaningful dialogue about how to fix it beyond screeching.