People Are A Complicated Mess Of Ridiculousness...

I will never understand people as a general whole, I just won't, people every day are doing things that I just cant wrap my head around. Some of these things are more tragic than others like murders, abuse, etc but there are plenty of little things that are just as confounding. Take, for example, the following example: We have a female with children fighting a horrific custody battle with her exhusband, her current significant other is constantly berating the selfish actions of the exhusband. Recently the couple was talking and the female made a joke about how breaking up with her would solve whatever it was the boyfriend was complaining about. The boyfriend responded that breaking up wouldn't solve anything because then he'd have to fight a custody battle with her for their daughter and would hate her if she won etc etc etc.... Please explain to me why people feel its ok to vilify one person for actions that they know darn well they would do themselves in the same situation. This guy has nothing good to say about the ex husband talks about how he's a selfish POS for what hes pulling etc but without even blinking, totally serious as a response to a joke with no hesitation he proclaims his intention to participate in the exact same behavior he abhors in the other person if she and he ever break up. This makes NO SENSE to me. That's like crap talking a smoker and refusing to date them then going outside and lighting one up yourself. WTF?