That every other website in existence is behaving "badly?" Do you think Chrome should tell the website that the user is browsing in incognito mode so that websites will treat them differently? For example, a paywall website with a free article limit would simply not show content to users saying they are in incognito mode.
Enabling incognito mode in Chrome and Firefox even explains that it doesn't stop server-side tracking, so it's not even misleading.
There is DNT for example, which can easily be used to transmit the user's intentions automatically and without unnecessary interaction. The technical means are there, they just need to be enforced, which maybe this lawsuit will improve...
It's the website's responsibility to respect DNT=1, then not load the ga script. DNT is not widely adopted and there are no legal mandates for it. It is simply an expression of preference. Blocking third party scripts and third party cookies is something you can set in all browsers which will block GA.
Enabling incognito mode in Chrome and Firefox even explains that it doesn't stop server-side tracking, so it's not even misleading.