Fair enough, but even the tenured professors were untenured at some point before so they did matter and were not problematic enough to deny tenure. And tenure doesn't really apply the same for adjuncts or some lecturers, who are perhaps even more dependent on student evals. And of course it depends on the seriousness the university takes teaching, as there are R1s that are more research oriented and care less about teaching, but they account for 1% of all universities.
Even as a grad student, my teaching evaluations couldn't negatively affect me. The only people it could have real, negative consequences for were instructors, who work on contracts. As an example, my department head (perhaps unintentionally) sent everyone an email saying any scores of less than 3.73 on a 1-7 scale were grounds for termination of that instructor's contract. I did not envy them at all, basically being highly educated customer service workers.
