I don't really like Mr. Stamos because he has been saying everything he can to discredit Facebook since he got ejected after a row with management. This could just be my perception of him but I don't find his arguments to be entirely in good faith.

Denying E2EE is a cost as you are punishing people for the crimes of another, this is depriving them of their hard-earned freedoms and liberties, for something someone else has done or may do.

Look at the activism going on today. BLM, dissidents in China, the rise of oppressive far-right governments in Europe like Hungary. I am sure if you dig far enough, you could find many people fighting in obscure causes, high profile causes, in a number of countries, who would fear the fist of an oppressive government.

What if the FBI / NSA decides to surveil BLM, as they already are? What if the CCP strikes down a dissident as they already have on Zoom? What if Orban decides you are a secret agent of George Soros plotting to undermine the government? Is it the case that everyone should roll over because a criminal might use the same means as them?

There is also a cost in not having your smart TV microphone record all conversations and upload them to the police.

That's a false equivalence. At any point in this, there is little we can do to verify E2EE, but trust a 3rd party. We can trust that they enable it, or as previously proposed we can trust that they are visibly in the meetings and observing. Either way, we have no way to ensure this is true when dealing with 3rd party providers.

Your smart tv recording has nothing to do with this, but one does still need to trust that it isn't happening. In the case of the smart tv we can attempt to look for microphones or other components that are able to be used as microphones. Software offers a more difficult path in verification.

I have no idea why verification, or other technical details, would affect the ethical calculus of having our conversations spied upon.

People who wish to mask their crimes have a greater incentive to use E2EE so will probably gravitate towards platforms that offer it. I would therefore suggest those not committing crimes are disproportionately affected by E2EE not being made the default where possible. Once one service in a particular category offers E2EE, the benefits of the other services in that category not offering it is significantly reduced.

This is only true if you assume that the world is populated with an equal number of criminals and non-criminals.