I love it. Pilots that know MORE than the manufacturers who designed and built the airplane.
I'm not sure if this is what happened at LGA but anytime you get the airplane out of alignment with the centerline on a contaminated runway, you have a component of that reverse thrust that is directly pushing the aircraft off the side of the runway. If there is a crosswind and the aircraft has weathervaned, that reverse thrust is just going to make it worse - whether it is applied asymmetrically or not. That is why it is not recommended to try to salvage the situation with asymmetric reverse thrust.