Long winded oversimplification man to your rescue!
Both ingress and egress filtering are Internet standards.
If someone is an Internet Service Provider, and they are selling what they claim is Internet, but they are not implementing ingress and egress filtering, then they are committing misrepresentation or fraud. Because what they are selling is not Internet, by definition.
For comparison, suppose I set up a truck stop and sell fuel from pumps marked "diesel fuel". As long as that fuel actually conforms to the legal limits for sulphur content and the ASTM standard for diesel fuel, I am OK. But what if I am actually pumping gasoline out of those pumps? Well, after a few truck engines catch fire or explode, I will go to jail because I lied about what I was selling. The standards are what determines the fact that I lied.
Anyway, what ingress filtering does is it says "I will not let anything in the door that is not intended for one of my subscribers". So, if something says it's for China, I won't allow it to enter New York City, because that's obviously misrouted and should fail according to the standards.
Egress filtering is even more important; it says "I will not let anything out the door that does not have a source address of one of my subscribers". So, if something says it comes from Egypt, I will not let my customer send it out of my network, since it's obviously got a forged return address and thus only useful for harmful activities.
So this should be simple and straightforward - if you are claiming to sell Internet, but you aren't following the standards, you are already committing a crime, there's no need for any new laws.
There are two problems.
One, many ISPs are telcos. American telcos are basically not subject to the rule of law (thanks, Obama). So it's a bit of a sticky wicket there.
Two, judges are picked politically, not on technical merit, and juries are often picked to represent the least common denominator of the American public. That really strongly decreases the chances of anyone in a courthouse having the technical and literary background necessary to cut through the lies of large wealthy corporations. It doesn't help that the standards documents are called "Requests for Comments" (no, really, they are).
Note: Verizon, AOL, and many others violate the standards routinely. Don't expect them to go to jail any time soon.
In the case of ingress and egress filtering it's not about traffic content. It's very much like utility regulation - a US utility is required to send you electricity between 112 and 125 volts, at exactly sixty cycles per second. If they don't, they have violated the standards, and your dishwasher will burn up or your electric heater will explode. Just so with Internet standards - they are not about content, they are about what is and isn't a reasonable behavior for a participant in a workable system.
The Internet is not made of wires and computers. You can send data packets by carrier pigeon and it is still Internet. The Internet is made of rules. If you don't follow the rules, it's not Internet, just as gasoline is not diesel fuel.