Most people think that if you're warned that the lane is ending, you should do something sooner than later. They also know that if they wait until the last second to try to get out of that lane, then they're at the mercy of someone letting them in, so most people get out of that lane as soon as they can.
Then they sit there, and anyone who goes flying past them in the now-empty lane is seen as somehow cheating the system, taking advantage of all the people who abandoned that lane. They're seen as dicks by the people who thought they were all doing the right thing by getting out of that lane. It based in ignorance. People don't know that using both lanes until the last possible moment and then zipper-merging is the most efficient way. And it still depends on others "letting you in" at the end, which doesn't always happen, so people aren't necessarily wrong for playing it that way.