The things they're calling legitimate use just isn't, which is why they need banners.
There are some analytics companies out there that advertise cookieless analytics, but they are either a) too simple for enterprise or b) a much, much worse privacy and compliance risk.
It's admittedly sound advice to create a banner for such a usecase however, as sanitizing all user data from these events is hard to guarantee, and you'd have to do just that to keep it legal
Many times, the user IP, which is considered PII, is stored in various servers/routers log that you have no access to...
When it comes to processing other people's data you don't get to do whatever you want.
Maybe try running a website without analytics before throwing a tantrum.