I mean, have any of you seen a male tsundere or the like smack around his girlfriend, and have it laughed off as funny? Hmm?
Actually, yes, I do. Although that character is from an anime made in 1974 (and it was not aired in USA, as far as I know), so maybe it is a weak rebuttal, but the fact remains.
Regardless, Tetsuya Tsurugi from Great Mazinger was a tsundere. If you have watched Evangelion, the only differences between Tetsuya and Asuka is the latter has boobs and red hair. Anyway Tetsuya ocassionally hit Jun -his love interest and adoptive sister- and it was treated llike comedic. Let's think of it, Jun was also a tsundere, and when she slapped him it usually it was not treated like slapstick, but she getting angry and losing her temper because Tetsuya had said her something very offensive -or dumb. Or both-.
I don't remember right now more male tsunderes. And regarding non-male tsunderes hitting females in a slapstick way... Hmm...
It sometimes happened in Mazinger-Z/Tranzor-Z, and many of those times I thought it crossed the line and it was not funny, in spite of what the animators intended (and they altered the characters' original personalities. Manga Kouji might be somewhat jerkish sometimes, but usually he was nice and considerate, and manga Sayaka was a pretty non-violent tsundere; Anime Kouji was a big ass and a sexist, and often I asked why Sayaka did not kill him).
Talking again about Urusei Yatsura, in a late chapter Ryuunosuke was running from Nagisa and he hurled at barrel at her head to stop her. However, everyone -including the readers- thought Nagisa was a girl at that point (his true gender was revealed shortly after), and Ryuunosuke looked like a boy. When I read that scene I thought usually in this series the abuse is from a female to a male, and I wondered if it would be so funny if it was visually obvious that it is a boy hitting a girl with a blunt, heavy object.
Mm... I can not think of more examples right now. There certainly a double standard here: violence visited from a man upon a man, a woman upon a woman or a woman upon a man may be made funny, but often violence from a woman upon a man is considered unamusing and unacceptable.
Then again, I have found another double standards such like a male character can be an annoying, loudmouthed jerkass...and fans do not mind. But if a female character has bad temper, fans call her a b***h and scream for her head on a platter. And then you have people does not care if a male character is useless in a fight or little important plotwise, but if a female character is not the Second Coming from Xena Warrior Princess or Lara Croft, she is useless, a waste and should disappear.
Sadly, entertainment -and fandom- is filled with double standards, discriminating against a gender or against other. Unfortunately, often when a writer tries to avoid to be sexist against women falls into the trap of being sexist against men, and vice versa (it reminds me of a fanfic I read once. The writer pledged he was not homophobic and intended his writings reflected that. However his fics came across like offensive to gays to me despite his good intentions. You'll see, he turned ALL female characters in bisexual, even if they were straight in the original material, and wrote many scenes where the girls kissed or groped at each other. Of course, no male character did become gay or bisexual. Thus, his attempts to not be homophobic read like a yuri fanboy fantasy). It is a complicated issue...
It does not help the tsundere trope has suffered what in tvtropes call the bane of all trope: follow the leader plus trope decay. At the beginning, tsundere characters were characters had both a soft and a harsh side. Their different sides were intended to show they were conflicted, complex characters, and their lively temper was intended to show they were not doormats, and it made them standing out among the mass of demure, soft-spoken characters were the norm back then.
Or at least that was the situation in the seventies and the eighties. Later the trope began degenerating. "Conflicted character with several sides" became "abusive girl hit guys secretly loves". Before their mood shifts and reluctance to reveal her feelings were justified -usually being due to inner tensions and conflicts- and explained within the series; now they had no reason. The character had mood changes and refused talking their feelings over because... because. She is a tsundere and that is what the tsunderes do, no reason is needed. This happened because newer series played the trope with no knowledge or understanding of it, missing what did that trope good. Cause that degeneration, the erstwhile new and fresh trope became trite, shallow and open to parodies, subversions and worst of all, deconstructions.
Moreover, tropes go through a cycle. They are born and become popular. Then they are used, overused and abused, and people gets tired or sick from them. Then they are parodied, subverted and deconstructed. After that point, they may be forgotten or they may be rescued and made popular again -and then the cycle begins anew-.
Back in the seventies, tsunderes were a change from the prevalent and overused female archetypes were used back then and some people started to accuse from sexism. Now the trope has become prevalent, overused and regarded like stale and sexist. So the former female archetypes are slowly becoming popular again.
) although I can count only handful when she hit him in part 2 manga. Of course NH pairing! No need for explaination there... 
Kishi's fault of lack of further development thus being very overshadow by Naruto & Sasuke. Yet the three are stronger and weaker than each other in different ways despite many opinions!
They act like all she does is hit and she doesn't. Besides, Sakura hasn't been a b**ch in a long time now. She's usually very polite and kind to people, so what if she's a little short-tempered? Never mind the fact that Sakura doesn't hit Naruto nearly as much in the manga as she does in the anime.
