Results show that oxytocin creates intergroup bias because oxytocin motivates in-group favoritism and, to a lesser extent, out-group derogation. These findings call into question the view of oxytocin as an indiscriminate “love drug” or “cuddle chemical” and suggest that oxytocin has a role in the emergence of intergroup conflict and violence.
https://www.pnas.org/doi/abs/10.1073/pnas.1015316108

We report here the results of a double-blind, placebo-controlled experiment showing that the hormone oxytocin promotes group-serving dishonesty.
https://www.pnas.org/doi/abs/10.1073/pnas.1400724111

In the semi-natural environment, the mice at first displayed heightened interest in one another, but this was soon accompanied by a rise in aggressive behavior.
https://wis-wander.weizmann.ac.il/life-sciences/what-does-%E2%80%9Clove-hormone%E2%80%9D-do-it%E2%80%99s-complicated

Their recent study — published in Emotion, a journal of the American Psychological Association — shows that in healthy young adults, too much oxytocin can actually result in oversensitivity to the emotions of others.
https://www.concordia.ca/news/media-relations/news-releases/cunews/main/releases/2014/01/21/oxytocin-and-oversensitivity.html

And now it makes sense doesn't it?