There's an extension that allows you to hide incognito mode from websites called Hide Private Mode I'm not sure why browsers don't do this by default (maybe it's some funny compliance thing) it would greatly improve privacy.
Cookies are not evil per se... but data mining companies made them like that.
I'm administrating an online store and cookies are responsible for the customer's cart, plus their user session / logged in state.
As an admin I adhere to the "golden rule", thus there are no creepy trackers on store. I don't like them and I don't want customers to face the same thing on websites that I manage.
That said, cookies are needed for user session & fraud protection. Instead of nuking cookies we shall kick the trackers out.
You need to track the user for a poll. Sessions don't work since private browsing enables duplicate votes. Tracking the IP can block users from the same network/wifi. Cookies get auto-sent and browser storage is only clientside. Really not many more options aside from making an account on a site and logging in. I find it a pretty reasonable solution actually.