But you can comply with ethical business practices without hiring employees to deal with hundreds of thousands of callers. Automated moderation is a thing, and actually responding to support tickets instead of ignoring them is also a thing.

I think you underestimate how many services you rely on that wouldn't be able to survive with a legal requirement that they were required to take calls from any human that wanted to contact them. Presumably those services are useful to you and you wouldn't want them to be closed down, yes? And similarly, you wouldn't want to be paying the $50-100/month for each service that would likely be required if every single one had to support a fully-staffed call center to deal with not only customers but potentially affected non-customers (as in the Giphy example in the parallel comment thread).