I hate this ad...

If the trail is that soft & muddy you shouldn't be riding it.
Period.

Seems like that I kinda sorta remember something to that effect that being one of IMBA's Rules of the Trail

Oh yeah, it is.
Its #2:

2. Leave No Trace
Be sensitive to the dirt beneath you. Wet and muddy trails are more vulnerable to damage than dry ones. When the trail is soft, consider other riding options. This also means staying on existing trails and not creating new ones. Don't cut switchbacks. Be sure to pack out at least as much as you pack in.

And yet IMBA's logo is at the bottom of the ad.

But I get it. Its all about the money