They are ensuring that you cannot pass and get in front of them. It is common here in Utah. AND they LOVE to slow down to 35 and merge onto the Freeway, which is traveling at 85...

When traffic is backed up to a standstill, and people try to use an ending/partial lane to pass 100 cars and then force their way in, I will indeed impede them in this manner, and it is indeed right.  If it's an exit lane, you have to give them the benefit of the doubt, but when it's 2 lanes closing down to 1, already narrowing, and all they are doing is trying to pass people waiting their turn, cry me a river.

To do so to prevent a normal merge into moving traffic is reprehensible and wrong, but those that feel they can force their way in at the front of the line are also wrong, and deserve to be messed with.  They can drive off the road if they feel they are that much more important than the rest of the stopped traffic.

 sweet, nice job oddjob3422.  Let's tell a story.  I55, entrance LaGrange road in ILL.  This is a LONG entrance way, yet for some reason does not go another 1/2 mile to the 294 entrance/exit way.  At 4:30 pm traffic, it needs all 4 lanes going south.  I   near the end merge as I am LaGrange road traffic entering the freeway.  Is it RIGHT that the JACKASS behind me is NOW going to go in the SHOULDER to try to be an inconsiderate prick and get in front of me?  Mindful, I am NOT half in half out, but the guy in front of me IS.  This guy in front of me gets in lane 3 at the same time jackass behind me is being an inconsiderate jerk, so I stay next to him and not back down.  At some point at the end, someone else was CONSIDERATE ENOUGH to PULL OUT of lane 3 and see this and pulled in front of him.  This guy let me in, pulled himself in, and jack ass had to pull behind him. Many a time have I seen lane 3 traffic jump to lane 4, but do they deserve to...if they are being inconsiderate and cutting me off to do so, yes.  at that point, it is nice to see a semi doing the halfsees if this 4th lane is nearly full of LaGrange traffic already.

oddjob you are actually making things worse, if traffic is backed up it is more efficient (and safer) to use the entrance lane all the way to the end because you end up with a single merge area instead of random merges all over the place.

A few examples:
PennDOT posts signs telling people to use both lanes until the merge point.

MNDOT has this website: http://www.dot.state.mn.us/zippermerge/

No, not true SoxFan. 

When traffic is in motion, zipper merges make sense.  When traffic has merged, and is at a standstill, it is not appropriate for other drivers to go past dozens of cars and then force their way in at the front of the line.  Those people are selfish and rude, and are not trying to create a zipper merge, which is simply not there in that scenario.  You need to consider the context of the situation.  You have to include, in your analysis, the state of affairs as it exists on the road.  If everyone else has merged, and some clown comes up that feels they are more important than everyone else, I really don't feel like they have the right to pass everyone.

Impeding that one person in such a situation does not substantively impact the traffic flow on the road.

If everyone were going all the way to the merge point, and alternating there, I would agree, and I would be happy if things ran that way, but typically they do not.  People merge in early, when they see the signs, usually miles back, saying "Left lane closed ahead.  Merge right" or vice versa.

Beyond this point, it is simply insane to go all the way to the endpoint before merging over in the first place.  You merge over when the space is clear.  It's like a Toyota driver that pulls a glaze eyed, no look merge at the end of an acceleration ramp.  You don't just lurch over at a specific point, you are legally required to yield the right of way to traffic in the continuing lane.

 oddjob you don't make to much sense. What you are saying is that a car should get over as soon as they enter a highway or see a sign a mile down the road to merge. That makes no sense. If I'm entering a highway and it's backed up I'm going to go all the way to the end before I merge. If I pass 200 cars to bad. There is no law that says I have to merge as soon as I get on the highway. If I'm already on the highway and then go on the entrance ramp then I'm wrong and that is against the law to do where I live. If I see a sign a mile up the road to merge either left or right and I'm in that lane that has to merge I wait until I get up to the merge point. No law says I have to get over has soon as I see the sign.

If I am in stopped traffic or in the zipper formation, If someone uses the breakdown lane to gain advantage I will block them from doing so. They are not special and can wait like the rest of us. I also like the look on peoples faces who have had a few miles of heads up about their lane is ending and then look in shock because I wont let them in....poor planing on your part does not constitute an emergency on mine.

I admit that I will block someone who had plenty of time to move over especially when they pass other cars who left them a space to safely pull in. In Utah this happens a lot when a lane if about to end or on a merge. Sometimes people get going at speeds that they cannot safely stop and assume drivers can safely let them in then slow down to 20 MPH below the speed limit or speed traffic is driving. I especially like the ones who can safely pull behind me but for some reason they will do anything to get ahead of you. 

  If someone is ACTUALLY MERGING, I will let them by. If someone thinks they're gonna use the merge lane to pass me from behind simply because they think they're better than everyone else, I jump in front of 'em! If you can't wait like the rest of us, leave your point of origin a little sooner.

You merge at the merge point & take your turn, just like in Kindergarten. People in Pittsburgh don't know this, & get angry if you use the merging lane to the merge point, as you're supposed to do. Morons. On the other hand, people who drive on the shoulder trying to avoid this rule, then get angry when they eventually have to merge, should lose their privilege to drive.