alt Hacker NewsThe excessive scraping and ignoring robots.txt only breaks the informal social contract established over the past decades of the open internet.
The real problem is the companies offering money to developers if they include unrelated SDKs in their calculator or flashlight (for example) applications. Those SDKs add functionality to incorporate those devices into a network that can be used for scraping. The traffic is little, but is distributed over millions of residential devices all over the world, making it difficult to categorize or block. That should be illegal, and that's what Google et al can be expected to be policing on their app stores.
On what grounds would it be illegal though? Things don't become illegal just because you don't like them. They may become illegal just because the president doesn't like them, but I don't think you're him, and in the absence of that, there has to be a majority of Congress and most of them want a reason.