The problem is that panel 3 men exist at all
Panel 3 women do, too. Some people are just shitheads.
society normalizes it to be like that.
That's simply not true. There is a reason neither men nor women are ever the ones willfully broadcasting this behavior: society absolutely does not justify this behavior. It's invariably the one on the receiving end calling them out (and the fact that it is seen as "calling them out" in the first place is more evidence that it is not a socially acceptable behavior).
“Men will be men” and all that is the problem.
Can you find a single, solitary example of a man being shown to react immaturely to being rejected posted online somewhere, and anything even close to the majority of the response being anything resembling "men will be men"? I contend you're fabricating this.
I totally get why women would be guarded because of it.
Do you also "totally get" why someone wouldn't trust black people after having a bad experience with a person who is black? Because this is the exact same line of reasoning white supremacists use.
Our job as men is to point out toxic behavior when it happens.
It's not men's job to socially police men. It's everyone's job to socially police everyone. It's ridiculous to insinuate that it's any more a male's responsibility to call out bad behavior, just because the one behaving badly is also male.
I didn't say it did.
What it does do is equivocate the 'panel 1 men' and the 'panel 3 men', and by pointing out the hypocrisy of those two behaviors, they are therefore implying that you're a hypocrite if you say what's in panel 1.