You never knew to begin with, now you have an explicit reason to realize this. Any black box run entirely out of your control, where you can never verify the output, is subject to the same suspicion.
“Fool me once, shame on you. Fool me twice, shame on me. Fool me three times, shame on both of us.” -- S. King
Some things are more obscure than others. It's easier to trust and verify Office SaaS than AI SaaS. The determinism and obviousness of most other activities make them less susceptible to hidden interference. AI run by someone else is the next level of black box for users compared to most other objects or services we usually interact with.