Aren't there libraries/frameworks/products for exactly this? E.g., when I google "website tracking framework" amplitude.com is top ad result, and it seems to cover the business uses. And http://google.github.io/tracing-framework/ is the first non-ad result, which seems to cover the legitimate technical uses.
> I believe most of the site-owners need these information to operate/develop their sites
Can you give an example of a piece of user-relevant functionality that cannot be implemented without Google Analytics?
IME especially Google Analytics is mostly useful for business reasons, not technical reasons.
It's certainly fair to say that it's difficult to operate a profitable web business without Google Analytics. But that's a very different claim. And the difference is important because...
> So, if anyone could simply explain why this is SO bad or send me to correct discussion
Legitimate customer-business relationships should always involve informed consent. Cookie blockers and Firefox containers provide the technical tools that enable me to make an informed decision about whether to use your site. Without those technical mechanisms, it's very difficult for me to constantly monitor whether you are tracking me.
You/Google are free to deny me access to your products/content if I choose not to be tracked. But I should be allowed to make an informed decision about whether to use your site. The tools you're complaining about enable that informed decision.