Not as bad as barging into a rider though which is what we are discussing here.
You said it yourself that the earth is not flat. Hence the discussion is not only about the party you would like it to be. And to end there. Roglič was not last in the line. Hence there was still something going on behind him. Influencing the outcome of this incident. It was not a hay bale. To say the least.
The question we came down to is. If the rider in front of you deviates from the line. Do you get a free pass in crashing him out or not. Or is it your duty to do everything in your power to save the situation. This is what we are discussing now. Roglič and Wright already did their part. And are now already focused on Il Lombardia and WC. They are really not that important in this discussion anymore.
People saying it's 100% Roglič fault. What they are actually saying is if the rider in front deviates from the line. The rider coming from behind. As long as he doesn't deviate from the line. He can crash the rider at front and there is no offense involved whatsoever under no circumstances.
In my opinion the answer here is clear. You don't get a free pass. As a rider coming from behind. It's your duty to save the situation. For it to not result in crash.
Or for an analogy. If you are riding on a highway and the car in front of you is starting to move into your lane. You have plenty of time to acknowledge what is going on. As the rider doesn't see you in his rear mirror the crash is imminent. If you don't do something about it. Now if there will be a video. Where there was no tail lights. On top of that a massive acceleration to be detected. Resulting in a crash. Or lets say somebody stole a couple of eggs from your basket. And you shot him.
Goof luck with the judge.
I can understand on why some people would rather stay at superficial take on it. As it aligns with their claim nothing can be done.
That is not true. In this case crash could be avoided if the rider coming from behind would back off and use other alternatives. Like use rider in front as a lead out, pass him latter on or from the other side. Or to at least shout out. Get out of my lane. Anything. To avoid the crash. Or if the sprint was ruined to relegate the rider in front after the race.
That is how it should be done in modern cycling. This is the standard.
In this case in my opinion the offense is nicely distributed in between both parties. One riding without due care and attention and the other one riding recklessly. But feel free to have other opinion.