Why do people just cut lane at the very end of a merged road

You know how annoying it is for those drivers who stay on the lane that's open and others just rush all the way to the end of the merging closed lane. It's really stupid. This creates a massive slow down for those who stay on the open lane. And guess what!? both lane will come to a full stop because of those trying to pass someone on the closed lane. The earlier you adopt to the open lane the faster the traffic will go. I really hate those selfish bastards who ignore the rest of the drivers on the road.

I'm always actively yielding the other drivers. Please learn how to driver smart and don't be a prick please...It wasted me 30 mins to get to my office with a little more than 3 mile driving distance.