There will certainly be times when the Go-Pedal (throttle) is the right tool for the job. Just not very when off-roading, unless you are mud-bogging. 99% of the time, out on the trail, you shouldn't be spining your tires like you're a nitro drag racer doing a burnout. As for most most things in Off-Roading, there is no “abosolute rule” to this as anyone can come up with scenarios where throttle IS the right answer, but more often than not, spinning the wheels when off-roading will either break things or just dig whatever hole you are in deeper, or both.
If you are already stuck, one of the worst things you usually can do is put your foot down on the accelerator. Ironically, this is, more often than not, the first thing people new off-roaders do in this situation. You should fight that urge. If your wheels are spinning and you are not moving, you are only going to dig in more. The longer you stay on the gas, the deeper your hole gets, and the harder recovery will be. The likehood you are about to need replacement parts goes up too.
Spinning wheels on a 4x4 can often cause you to slide or drift in whatever direction the road leans. This will seldom imporve your situation and on many of Montana's thin trails and can occasionally be a really bad thing.
Avoiding tire spin when you are being recovered is also the best plan . A gentle bit of throttle may help to get you back onto solid ground, but there's certainly no need to have your car bouncing off the rev-limiter. In snow or soft sand, it is sometimes better not to even touch the throttle and allow your winch or the snatching rig to pull you out. Let your rig roll out of the hole and back on top again. As my mother used to tell me "When you find yourself in a deep hole...stop digging".
The old adage that says "When in doubt, power out" might work every once in a while, but it is generally for people with more spare parts, spare time and spare money than I have.