I was procrastinating answering this question because I was going to think up the most detailed and convincing explanation I could think of.

then I realized that there is no need for that and I’m just gonna say this from the heart.

despite any mistakes he might have made, there is no denying the fact that John loved his kids. He cared about them and everything that he did, he did with them in mind, to protect them.

You can even compare him to Cas if you think about it.

Cas messed up a lot. He constantly made mistakes and chose the wrong way to go about completing his goals. In desperation to get his friends to understand what he needed to do, he teamed up with Crowley in order to open purgatory and get the souls that he figured were necessary to win the civil war in heaven. He knew that Dean wouldn’t understand what needed to be done, and thought that lieing to his friends was the only way. He later realized that if he was upfront about what he wanted to do, Sam and Dean would have worked with him to figure out another way to help him win. Despite any of this, everything Cas did was with good intentions. He would never put his friends in danger, and he might have gone about it the wrong way, but he will always protect Sam and Dean.

now how can you compare john to cas?

easily

John knew there were monsters in this world. He knew that there was a demon that killed his wife, in son’s room. After that, he was desperate to protect his sons from all the evil in the world while simultaneously seeking revenge for what happened to Mary. The way he went about this may have seemed flawed at points. But didn’t Cas make the same mistakes? John’s intentions were always good, and the only thing he had in mind was protect his boys and kill the son of a bitch who killed Mary. Yes, he wasn’t around much. He gave Dean an awful lot of responsibilities at such a young age, and seemed pretty angry when Dean failed to follow an order. He may have been a bit stricter than he probably had to be, but if there was even one mistake, one flaw in the “system” persay, his boys could have gotten hurt. Dean didn’t follow an order from John once and Sammy was almost killed. John did what was necessary to keep them safe. It also may seem as if he expected too much from Dean, and yes Sam and Dean didn’t much of a childhood, but his intentions were good. He made mistakes, and sometimes the way he went about things was flawed but—

wait a minute, doesn’t that sound exactly like Cas?

How come Cas can screw up so much, with good intentions, and everyone forgives him, but John messes up too, all with good intentions, and everyone hates him? 

I also do not believe John ever abused Dean. No.

Also John sacrificed himself to save Dean????? Did everyone forget that???

so don’t ever tell me he didn’t love his kids.

He has been through a lot in his life, but he always has and always will love his kids. Yes, sometimes he should have done things a little differently, and he may have gone about some things wrong, but at the end of the day he did what he did his boys in mind, and did what he thought he needed to do to protect them.

so there idk what else to say