I agree with the thought and intention behind this 100%
Most people will understand a volume control button/slider as something that you can increase the volume with.
But a technician will rightfully say, "no, it's a filter that attenuates the maximum possible volume".
I agree with the OP that it would be obvious and desirable to have the option to completely disable attenuation, and make it clear to the user that it has been disabled.
(if it was only for the users that aim for bit-perfect playback)
While MusicBee has a clear visual indication that attenuation is applied to the max (a.k.a. mute), MusicBee doesn't make it clear at all when attenuation is disabled. (volume = 100%)
It's close to impossible to see if the volume is e.g. at 95% (attenuated) or at 'pass through' 100%.
So I support the wish, but I would suggest it would be much better if it is not hidden in some preferences>player>blabla setting, but in plain view, integrated where it makes the most sense:
The same location of the mute button and the volume slider.
So 'mute', 'volume slider', 'attenuation disabled'.
It would make perfect sense, but somehow my hopes for something like this are low.