True, but it is obviously exagerated for comedic relief. In truth, I doubt she would do more than a light slap (that doesn't hurt at all) for the sake of making sure he understands. She thinks that he tripped on his own - in other words, he was careless, so she would rather make this lesson stick, than him dying from carelesness. Besides, she obviously loves him, while that other guy's father was simply abusive.
Sure, I would never hit my kid, nor is it normal in our culture, but in asia hitting a disobedient child as a disciplinary action is still all too common, so to them the woman's actions aren't as outrageous as to us. Well, at least to the older generation it isn't.
I don't think the author meant to use abusive parents as comedic relief. And that wasn't abuse in the first place. She was just smacking him because he had caused her worry.
Parents in Asia find it normal to discipline their kids physically. It's a cultural difference, and it's something that I've experienced, and I don't necessarily think it's a bad thing either.
If that’s the case then it’s a cultural lost in translation occurrence here for a western reader. I personally just don’t find it endearing hitting your child who’s in the hospital. Moreso for the audience to see this after they’ve read severe child abuse and assume this is meant as light hearted relief. It’s fall flat if you take it at face value and worse as I said before devalues the point that hitting a child as really abuse rather than the “love” our villain was provided. I understand what the author was trying to convey but again the scene is a moot point.
The author never used any form of abuse as comedy. She clearly portrayed the abuse of Jiho as something bad. Slapping your kid out if worry, isn't equal to abuse. And for Asians, that's many times the norm, slapping someone out of worry. You see it in Asian shows swell and its reality, and not particularly something bad. Connecting a normal Asian practice to ABUSE is ridiculous. That's clearly not the case and you are overexaggerating . The author clearly didn't portray it as abuse, and most people reading it have the knowledge about this Asian way of parenting, not the authors fault that some people who weren't raised like this and don't get it. Next time please try to understand cultures differ, and so comedy can aswell. (=・ω・=)
The tsundere trope is a whole other beast. I can somewhat get a parent giving their misbehaving child a smack for acting like an idiot, but tsunderes? Fuck tsunderes. They beat up their love interest/friends for no valid reason whatsoever. These characters are simply agressive maniacs with anger management issues that would earn themselves exactly 0 friends with their attitude. They are no better than bullies and I hate bullies. Harems, oversexualised lolis and half-naked G-cup ladies are up there with the tsunderes in my "absolutely hated tropes"-list.

Does anyone get annoyed when authors use abusive parents as comedic relief? The my child is hurt so let’s hurt them some more because it’s funny? It’s in such bad taste even more so when you give your villain character the origin story of being a child abuse victim hence his callous actions. The next chapter you we see a parent hitting their ailing son repeatedly because what it’s funny now? That kind of slap stick humor simply isn’t funny folllowing the reveal of such a serious character narrative and even cheapens the importance of it.