While certainly not excusing the stupidity of the fan, where is the outrage for the stupidity of the rider who caused the second crash?
A racer accidentally causing a crash is in no way similar to a spectator accidentally causing a crash.
A racer crashing is something that all of the riders know is a possibility, but a "fan" taking out most of the peloton is not something that should be considered acceptable in any way.
I can't imagine how mentally exhausting it would be to have to constantly scan the sides of the route for all the things/people that could possibly ruin your day, or kill you, there needs to be zero tolerance for stuff like this, because it is very specifically, easily, avoidable.