You have to trust the people that wrote the code.
There's a big difference between having confidence in open source code that has been audited by many people, and knowing for a fact that the service collects specific information. In the former case, you can never be absolutely sure that the code is not malicious so there is always a risk, but in the latter case you know for a fact that the service is collecting inappropriate information and you have to trust that people operating the service are not using it in adversarial ways. These two scenarios are in no way equivalent.
Which is fine, but it’s a choice to trust them.
It's a choice to trust the entire open source community around the project and all the security researchers who have been looking at the code.
Frankly, I have trouble believing that you don't understand the difference here and are making your argument in good faith.