Is it steep?
No
Is it long?
sort of.
At best it is a big ring steepish drag. Forget even needing a small ring on the whole route.
However, after 9 times going up it you will certainly feel the hill in your legs.
It's a nice ride, but if you are after steep roads then there are plenty of others that are 20% or so.
Should they charge?
Yes, or block off much of the hill. Without ticketing/charging the spectator numbers will be unmanageable. It is a nice area (I grew up cycling round there) but 100k spectators trampling and littering will do no end of harm and need to be managed.
Management costs money and the easiest way to do that is to close the area, which is probably the worst outcome.