I always find it funny how Hank ended up being "The wife beater" for years due to that incident with Janet, yet Spider-man gets a pass for doing essentially the same thing. Funny, in both scenarios it was also where the writer didn't intend it to look like a punch, but the artist messed up.
! In Hank's case, he was supposedly bipolar and this wasn't helped by a few high profile failures that he had while working with the Avengers, biggest that kept haunting him was that he created Ultron. This lead to him getting angrier and more unsettled as time went on (It's why he adopted the "Yellowjacket" persona originally) and he got to a point that he was using excessive force against villains. An incident happened where they were fighting a crazy person and Cap was able to talk her down and get her to stop fighting, but AFTER he did this, Hank attacked her again unprovoked. This was the last straw for the Avengers, and they were going to kick him out, but insisted he have an actual trial. They were basically court-martialing him.
! The barrage of horrible crap that had happened to him up to then, coupled with the idea now that he'd be the first person to be expelled from The Avengers made him snap, and he went legitimately nuts. He decided to pull a Syndrome from the Incredibles and build a robot to attack the team. Obviously, just like Syndrome, the plan would have been for him to stop it therefore redeeming himself in the team's eyes and preventing his court-martialing.
! However, he forgot about Janet. She went into his Lab and found the robot and the plans, confronted him and tried to talk him down, and then this happens:
! 
! According to Jim Shooter, the writer, "Hank is supposed to have accidentally struck Jan while throwing his hands up in despair and frustration—making a sort of 'get away from me' gesture while not looking at her." which, while still not good, would have been much better than what happened, which according to Shooter was that "Bob Hall, who had been taught by John Buscema to always go for the most extreme action, turned that into a right cross!". It being an accident is better than what was drawn, which looked like he straight up decked her.
This isn't helped by the fact that the dialog was still written as if he'd accidentally pushed her off of him with a "Get away" gesture, so he acts nonchalant about it like the thing he did didn't just make him a monster.
! However, Peter Parker does almost EXACTLY THE SAME THING to Mary Jane later during the much hated "Clone" saga.
! Pete had been going through some major trying times lately, the biggest of which was a villain who tricked him into thinking his parents were alive so they could find out the secret identity of Spiderman (having every single photo in the Daily Bugle of Spiderman say "Photo by Peter Parker" tends to make villains think Peter knows something) so just like Hank, the strain had all gotten to him to the point that he wasn't quipping to villains anymore, and was actually spending as much time as he could as Spiderman, saying he wanted to abandon being Peter entirely and call himself "The Spider".
! This unstableness came to a head when the clone stuff started and a genetic test was done that made it apparent that Peter was actually the clone and "Ben", the guy we thought was the clone, was the real Peter Parker. (This got retconned away, but at this point was treated as true)
Just like Hank, this straw that broke the camel's back, drove him nuts and he attacks Ben in a rage thinking Ben fudged the tests somehow, leading to MJ trying to break up the fight and calm Peter down, and he flat out punches her. Only, since Pete has super strength, she actually FLIES into a WALL had enough that you see chunks break off of it.
! 
! Just like the Hank incident, the writer Tom DeFalco states it was actually just supposed to be him lightly pushing MJ off of him, but thanks to his rage causing him to not have control of his super strength, she'd still fly into the wall.
! EXACT Same situation.
! The big difference, honestly, that makes me think of why people treated these incidents differently, is that tho both were intended to be accidents, Peters was the only one that was actually MEANT To harm MJ, Hank wasn't meant to actually intentionally hurt Janet to a real degree. The script flat out said he was just supposed to throw up his arms in frustration while he face was looking away from Janet. So he wasn't even supposed to have realized he even touched her. Therefore, Peter immediately realizes what he did was wrong and snaps out of it, showing remorse right then. Because the writer didn't intend Hank to hurt Janet or even know he touched her, he didn't write him showing remorse, so he looks like a monster straight out of the gate.
I'm not a Marvel encyclopedia, so I'm not sure what has been tried to fix this. Like, if Marvel ever tried to retcon the punch… I THOUGHT I read somewhere that one of the Time traveling villains (Kang is the one that keeps sticking in my head when I think of this) at one point revealed that he'd sent something back in time that messed with Pym's mind and ever so slowly nudging him towards madness, and over time that lead to the breakdown that he hit Janet during, but for the life of me, I can't find any info online that corroborates that. Since this is one thing I haven't actually directly READ and only heard about, I can't say 100% that I'm sure it happened. lol.
