I agree. Using data in the way user doesn’t expect is a cyber crime. In fact any web service have some sensitive information they should not disclose.
Look to the web service as to a program written by developers. It is completely their choice what to program there, what to get from the user, and what to do with the data they own, but this must be restricted by an agreement. The user’s right is to agree or disagree with the terms of the software and decide whether to use it. For example, by installing a software on a PC/Mac, we always read (ha-ha, or skip) the user agreement first, and press the “Agree” button. From this moment, the developers and maintainers responsibility to keep this policy apply, as well as for user.
When we interrupt the application’s normal behavior (like preventing it from sending some data which we agreed to share), this can be considered as violating the policy from the one side, as we agreed that the software has a right to collect our usage data. This can be the subject to stop providing services for us.
But actually no one do this “stop”, because this things are so trivial. If we “crack” the software (which can be compared by “patching” it with ad block) — who cares, do what you want and keep in mind that this is bad. But if we call to millions to install this patch, then this can be considered as something people should not respect.
So, coming to a conclusion, my opinion: respect users who decided to not to share their usage data only in the case when web services violate their own policy (which some regular websites do, and for which I believe ad blockers was originally designed). Otherwise respect those honest web services which keep their policy. And finally respect web service's policy itself. If it says that it collects your data, take it as is or do not use this web service.