[toomanybeersies]

User tracking and analytics, like most technologies, is ethically neutral.

It's how people utilise it that has an ethical/moral component.

[Nextgrid]

Even if your use of the collected data is ethical, exposing your users to a third-party's unethical use of the collected data is itself unethical IMO.

Using Google Analytics and similar services from companies whose entire business is built on stalking people is unethical and should be avoided.