Picture this: You are approaching an intersection and are planning on turning left. The car in front of you is slowly coming to a stop just before the turn lane and ahead you see a green arrow. If you don't catch that arrow, you are going to be stuck for a full cycle before getting an opportunity to turn left again. The turn lane is right there! If the cars in front scooted up just a bit you could go. Or... There is no one coming the other way. Maybe you could just scoot across the line and get into the turn lane so you don't miss that turn? What could happen?
Sure, there are much more egregious crimes than dropping a wheel over the line, but it is still illegal, and this van did a little more than barely cross that double yellow. As understandable as it is to cross over when no is coming, you, too will find yourself with a ticket if you do this in front of a cop.