We can have a little test - let's put backdoors on all of law enforcement's encryption usage and see how long it stays safe. I really don't know if people like Barr are arguing in good faith. But then I try to assume incompetence first and malice second.
This is an attempt to make sure ordinary people cannot have privacy, cannot be protected from either each other, other governments or this government, but wealthy people will continue to be able to buy that protection one way or another. It's a feudalist's proposition. You do not understand the motives without understanding the underlying ideologies. Not everyone can be a lord over their own data - it's a fact. Your data, peasant, is not your data! It belongs to your lord. And who the lord is case by case, it could be the government, it could be a particular corporation or a trade group of them.