"And so the public policy debate around encryption has been framed as a binary choice between two absolutist positions: either we allow law enforcement no access at all to encrypted data, or we must effectively give them complete, unrestricted access to all our communications"

Most people support giving some level of data access to law enforcement, but the problem is that there's no way to restrict it to just law enforcement. As soon as we give one person or group access to the data, then we've effectively given everyone access to that data.

Perhaps there was more in the presentation, but this is the only idea I see in the slides:

"Idea: Make brute force key recovery possible but very expensive"

Again, that assumes governments that actually follow rule of law, but any criminal is going to use stolen credit cards to rent for servers in the cloud (or a hacked bot farm) and crack that encryption at no cost to themselves.