Why is it dangerous? The lane is still open, the DOT has stated that the zipper merge is the preferred method. I agree that if the left lane is at a dead stop and a car goes flying down the right lane it could be dangerous, but usually that’s because someone in the left lane wants to control the flow and pulls halfway into the open lane, obstructing legal traffic. It would be the fault of the person splitting lanes should there be an accident, legally.
I believe it is herd mentality for everyone to get into the left lane and cause a bottleneck, which is WAY more dangerous than zipper merging. However, the psychology of this issue is for those stuck in traffic to get pissed off at someone doing nothing illegal or wrong because they haven’t fallen in line. Not letting someone in, just one car that takes up only a few meters of space, is also psychologically driven.
If I’m in the left lane of crawling traffic I will always let others in. And I don’t feel that makes me a fool. I’m not an enforcer or controller, either. Usually multiple cars over the space of the construction. It’s no skin off of my nose, and doesn’t get me all worked up inside over nothing. I sit in traffic and center my chi. What else are you going to do? Why not choose a better attitude and go with the flow.