"at least" means that, even though the automatic switch was a bad idea, "at least" it's still doing something useful.
Except its not. It's actively counterproductive. Anyone who tries to send to that address will incorrectly believe I will see their message, and yet I never will. For people like you it may be useful, but for people like me it is an anti-feature. That address should never have been made visible on my profile without my express permission.
Again, the only problem here is that they automatically switched the email address on your profile. If it was opt-in, then people who actually use facebook and want the feature (not you, clearly) can use it.
Even if they didn't automatically hide my old email address, merely making the @facebook.com one visible on my profile is an anti-feature. So no, the problem isn't that they automatically switched my visible email address, it's that they enabled a "feature" for me at all that turns out to be an anti-feature. Removing my real email from my profile was just the icing on that shit sandwich.
It's ludicrous to call that an "anti-feature." The feature may very well have been active on your account for years without you even knowing. Yet again, the only bad thing is their choice to replace your personal email address with their own.
Except its not. It's actively counterproductive. Anyone who tries to send to that address will incorrectly believe I will see their message, and yet I never will. For people like you it may be useful, but for people like me it is an anti-feature. That address should never have been made visible on my profile without my express permission.