Zumbo, I think you are over-reading or misinterpreting it. You don't use BOTH to bass manage SIMULTANEOUSLY. If you had a receiver that could bass manage it's multichannel inputs, you wouldn't want to bass manage in both places; you'd pick one or the other.
And even with the usual receiver that does not bass manage it's analog multichannel inputs, you still choose to either bass manage with your player OR your receiver depending upon your specific need and your specific preference for the particular media you are decoding at the time.
It's simple. The receiver's settings are not applied to the analog multichannel inputs, only the digital input. Likewise, the player's settings are not applied to it's digital output, only it's analog multichannel outputs.
Yes, absolutely, you can bass manage your digital connection with your receiver and your player's multichannel analog connection with the player. And even have completely different settings for each. But if you wish, you don't even HAVE to use the digital connection AT ALL if you have the 6-channel analog connection.
Sorry, I don't understand your complaint. The point is that you should (and in most cases CAN) only let ONE bass managing device bass manage any given media at any one time. You shouldn't bass manage something redundantly.