Xinmo

She actively insulted Wangfei in front of Wangye. By insinuating that his unknown people of unknown origins would commit bad things that of course are related to "certain activities" (Ch.19)

She actively participated in his downfall and helped her father work with Wangye's enemies and betrayed him (One example is CH. 71).

To quote:

"When the Count of Yongchang heard this, he looked like he had been struck by lightning and glanced at the fourth prince. Song An was already shaking like chaff being shaken off rice, and Jing Yu’s face turned white."

She didn't just run for her life, funny enough she's 'worried' about spies when she's the one giving out all the information. She held strict control over the other concubines and did a bunch of things that run from snitching to embezzlement of funds. She tries to murder Wangfei, and she gets imprisoned and slapped (by a maid) for that (Ch.74).

To quote:

"These two years, when the side wife was the one to manage the household, his monthly allowance of silver has never risen. The red envelope he received at the end of the year was less each year. Yet the few chambermaids she brought with her had quite a cushy and lucrative job. All the servants in the prince’s mansion were long unsatisfied with her."

“Responding to Wang Fei, for concubines secretly trying to use aphrodisiacs, their punishment should be to be beaten to death with rods.” Duo Fu wrinkled his bun-like face and replied honestly. This rule was also one that had been set by the Secondary Wife. Originally, it was just getting sent to the temple to become a nun. (Ch. 22).

"Mu Hanzhang frowned and roughly guessed what was going on. He didn’t know what had just happened at court, yet Song Lingxin clearly knew and had responded so quickly."

“The Cheng Wang’s house doesn’t raise ingrates who eat here but whose loyalty lies outside.” Jing Shao looked at her coldly.

She's not a good person. At all! She did this in his past life and in the current one. Sure, people can change. However, she's so stuck in her head and genuinely believes that she's in the right as she degrades Wangfei and his control over the house that it's clear that change isn't in her line of sight. She's a horrible person, getting upset for being slapped when she underhandedly attempts to have her fellow concubines killed, and then attempting to kill Mu Hanzhang with her own two hands.

Drop this manhua if you don't like it, and if you want to defend women who are being abused (I hope you also defend men) then go ahead. It's a good thing, and you should be sticking up for women and men who experience abuse. Just be sure to know the situation and who you are defending to your utmost ability.

That being said. I don't believe Song Lingxuan's punishment is inappropriate, not when she's caused the death or ruined the lives of others.