I share your surprise at ‘blow it up real good’ being dismissed as infeasible(especially since Colorado and vicinity have a decent amount of mining and quarrying activity; and those are industries where blowing up a rock real good is just another day at the office); but I suspect that man portable rockets would be an arduously slow way of doing it:
Depending on the specific model specs for penetration of concrete and masonry vary; but while generally high enough to make occupants of modestly hard cover nervous, they aren’t really there for bulk removal purposes(actual bazooka warheads I think are in the ~1 foot range; more modern ones will probably give you a meter or so; which is a harrowing prospect if you were hiding behind that wall but counts as ‘nibbling’ in the context of a huge rock).
For efficiency you need to drill into the rock so the charges go off internally and can more easily shatter it into chunks large enough to be hauled away. Bunker busters can do the ‘penetrate, internal exposion’; but I suspect that the Air Force takes a “you want us to bomb an American highway why now?!?!” attitude toward that idea; and probably can’t do the job more cheaply than the local blasting contractor.
