Ethin have you watched Karen's talk yet? She is behind both writing and enforcement of the law, she knows what she is talking about.
I've spoken with Karen in person in some detail about it, and to put it bluntly, you're wrong. You are misinterpreting the requirements, the exceptions, and the process.
"How do you think Valve has not managed to be pegged by the FCC for violating this law already?"
The FCC doesn't "peg" companies. Customers do. FCC work as mediators - when a customer makes a complaint to the FCC about a company, the FCC works with that company to get it fixed. Which in every case to date had happened promptly.
Every single case brought to date has resulted in the issues being fixed. Yet steam has not been fixed. Which means that the only possible reason is because no customer (or group) has raised the issue of steam inaccessibility with the FCC.