And once they've normalized "your computer will spy and inform on you", is there any reason to think that won't expand to things which aren't colloquially "computers" but in fact are now computers?
What about "smart houses"? All your IoT toys are computers. Once phones, laptops and PCs as mandatory reporters has been normalized, is there any reason to think all the other microphones and cameras already in people's houses won't become mandatory reporters too? If they make it illegal to disable client-side scanning on computers, might they also make it illegal to remove the crime-detecting cameras in your own home?
Modern cars already narc on people, logging and uploading GPS traces that can be fed into police dragnets, just like phones. Cops can ask for a log of who's been inside a 'geofence' and where does that data come from? Phones and cars reporting on their owners, generally without their owners knowing anything about it. The 'slippery slope' isn't actually a fallacy if you have enough datapoints to legitimately draw a trend line. And I think we certainly do.