This was the problem. Back in 2017 people said that Cavendish should have been willing to back down and cede the spot so there wouldn't be a crash, effectively giving Sagan carte blanche to sprint on the crab and block off the right hand side. Today it was Sagan being squeezed and he responded by forcing the issue. If Wout was 2017 Sagan, 2020 Sagan is flung into the barriers at full speed. Why shouldn't we hold Sagan to the same standard and ask him to back down and cede the spot? In the wake of the Groenewegen-Jakobsen incident we were all calling for the sprint to be better policed even if incidents don't occur, because it was by and large agreed upon that the reason sprinters think they can get away with sprints like Groenewegen's there is that they never get punished for them unless a crash occurs. We are a bunch of hypocrites if we then think it's unfair to penalise a rider for exactly that offence when there is no crash, just because he happens to be a (imo inexplicably, but let's leave that) popular rider and that it affects a jersey competition which has become more compelling than it has been for years. If what Sagan did had been done by somebody reputed as a dangerous sprinter, like a Bouhanni, it would just be cited as more fuel for the fire. Plenty of riders have been derided as dangerous sprinters over time. For some it's a pattern of misbehaviour, like Feillu or Bouhanni. For some it's one particularly egregious mis-step such as Ferrari or Groenewegen. There really ought to be enough material on hand now to say that Sagan is somebody you want to be careful around in a bunch sprint, at least when he's not at peak level. He seems to be a lot more prone to this kind of stuff when his form isn't there or when he's involved in a real fight, for whatever reason. Maybe it's that for somebody as naturally gifted as he is, he isn't used to fighting from a position of weakness, or the pressure associated therewith, I don't know, similar to Cavendish in 2010. Or maybe it's that he's always been that kind of overly physical, borderline irresponsible sprinter but a combination of his supreme bike handling skills and his pace especially in reduced bunch gallops meaning he's well ahead of the bunch usually so any tendency to sprint on the crab hasn't been curbed, I don't know and can't pretend to, I haven't closely studied a large enough sample size of Peter Sagan bunch sprinting for reasons which will be pretty obvious to anybody that's followed this forum for long enough.
It's also eased on this particular occasion, however, by the slight right hand curve of the finish in this stage which means that while the gap Sagan goes for is not really wide enough, it widens slightly on the road making a crash on that side less likely, which was not the case on the Vittel sprint three years ago. There was therefore enough room for both Sagan and van Aert to sprint after the contact and nobody got hurt, thankfully, but that doesn't mean there was no offence. To be honest I was surprised by the DQ in Vittel and thought the original relegation was not unfair as a punishment (though I wasn't going to complain about being able to watch a Sagan-free Tour, admittedly). This offence I believe merited the relegation, but was not as bad as the Vittel sprint, which I thought was a much more obvious offence.