It's wild to me that people's opinions of John (not factoring in personal bleed) are based ENTIRELY on the shitshow that was his life post-Mary death. Like people are out here measuring Sam's and Dean's heights to calculate the nutritional deficit in Dean's physical development but can't spare a minute to think about John as a whole character. Okay come with me for a minute:
you're John Eric Winchester from Normal, Illinois, and you're a pretty ordinary child, there's literally nothing exciting about you but here you are! You exist! You like yo-yos and guns and planes or at least that's what your parents buy for you.
your dad, who tends to go to work at odd hours, takes you to see an Abbott & Costello movie about a mummy when you're a pre-schooler and it scares the piss out of you. Your dad (who has intimate knowledge of the REAL things that go bump in the night) buys you a music box to calm you down. This music box plays a song from one of the most famous cinematic scenes of romantic melancholy that exists. Despite the late 50s being music box heyday with many options available that play lullabies, for some reason everyone thinks this is a reasonable choice. You will in fact idly whistle "As Time Goes By" all throughout your life.
when you're four, your dad abandons you and you never hear from him again or ever find out why he left you.
your mother Millie doesn't remarry. You have no family around (presumably?) so she raises you, alone, a single mother who can't even claim her husband died in the war, any war. You barely talk about your childhood even in relation to your own sons and how you raise them.
you play baseball/softball because where else can you find a readymade source of companionship and a built-in father figure (from a distance).
at seventeen full of anger and a dad-hole a mile wide you fake your age to join the Marines and be shipped off to Vietnam. While you don't talk about it much when you return to the World, you will default to drill sergeant when your back's to the wall.
you become a mechanic because you come from a family of mechanics.
you meet Mary Campbell and your whole future falls into place. Or at least, that's what you believe. Until November 2nd, 1983.
like there's ALL OF THAT before the John Winchester who's an enormous mess but does everything he can to keep his kids alive. I'm not saying anybody needs to like John but the kneejerk response of "he should be KILLED ACTUALLY" to even the canonically unequivocally good things he did while examining other characters' microexpressions down to the nth degree to ascribe victimhood is just so weird.