That's like claiming because you took pain killers and can't feel it anymore your leg isn't really broken.That's like saying the brakes on your car don't "cure" the inertia of it moving.
A strap is like an aspirin.
Maybe it's all you need.
Maybe it's the only solution you have available.
It won't ever make your leg not broken though.
If a strap keeps the headstock pointing in playing position when your hands are off the neck, what else is there to care about?
The added real weight on your shoulder that a neck diving instrument produces is something to care about. Weight is a big deal to a lot of people and I'm not sure some understand how many extra pounds (yes pounds) of pressure on your shoulder can be applied through leverage of a neck heavy bass.
I appreciate that a strap may solve the issue for some people and I'm not saying it won't. The only problem I have is when you say it will solve the problem for everyone when it clearly that just isn't true.