Very few people are interested in making data-driven decisions. They want an employee (subordinate) who will prove that the decision they've made or are planning to make, is correct. Anything else is, as you say, very internally disruptive.
Being a data scientist or data analyst at a startup is (for the most part) a completely miserable existence. You are relegated to doing interesting things that are usually discarded. It can make you feel like your job is pointless.
In the end, one either makes the decision to be (at best) useless, or (at worst) a puppet. That, or you quit.
Thank you so much for your comment - it's refreshing to see I'm not alone in feeling like this.