There's a difference between experimenting on the product, and conducting an experiment that deliberately puts one cohort of users in an environment hypothesize

There's a difference between experimenting on the product, and conducting an experiment that deliberately puts one cohort of users in an environment hypothesized to create negative emotions. A/B tests for the case where you honestly, in good faith, think both A or B could be good designs, but you don't know which one is better. A/B testing is for product design changes, not psychology experiments. It is NOT for the primary intention of a psychology experiment with a group of subjects that didn't consent to a study, where either A or B has a suspected negative impact on emotions, and you're using A/B testing to confirm or deny that hypothesis.