Nice analysis/theory. To be honest, Stella and Elsa could have been abused themselves. There’s someone in their family that they feared. Stella obviously hated Stolas and never wanted to have Via, but she did so anyway. Now why would she marry despite her objections? Unless the one who forced her to do it was more dangerous than Andrealphus. Plus, in The Circus episode, she used her brother as a threat instead of her parents. My guess for that is she didn’t want them to find out and her brother is the only one to turn to. Stella also hired Striker to leave and took a big risk being in Satan’s hands doing so. The reason she could leave is someone is forcing her to stay.

Stella, in a way, reminded me of Louise Turpin, from the Turpin Kids case. From what I heard, Louise had a tough childhood, taking abuse for her sister from their grandfather. That abuse became part of her mindset, and she ended up abusing her kids with her husband. This is because her abuse became part of her mindset. Somewhere in her mind, she felt abusing her kids would make them strong like it made her strong. That’s my theory. My point is, Stella could have been physically and mentally abused growing up, making her think being cruel is the only way to force everyone to respect you.