Your emotional outbursts are a behaviour, LadySuisei. Your lashing out in anger is a behaviour. You even did it on this site when you lashed out in anger and said horrible things about poster's abuse. Based on your various posts, both you and your son struggle to get a handle on behaviour when faced with stressors. There is professional help for such struggles. It's not uncommon and it doesn't make you or your son bad people. I don't doubt for one minute that you love each other based on your posts. It's a situation I find sad. My intent isn't to make you feel worse, only to offer perspective that you cannot see right now.
I don't want you to think I am commenting from a place of malice. I am commenting from a place of concern for someone who may self-fulfill an estrangement that neither party seems to want. I am a mother. I am a woman who has previously experienced great personal trauma, as has so many others who have tried to get through to you here. I don't want another mother and child to separate over fixable issues. No one wants families to break apart, especially when the family members themselves don't want to. Your son still sees you. I am only trying to help you preserve that and leave room for healing.
Your feelings on other people's estrangements and how others raise their children aren't really the issues you need to focus on. None of us are in a position to tell each what a "genuine" reason for estrangement is because we only live our own lives. We are not in a position to tell each how we should feel, what we should suffer, or from whom we should accept behaviour that considerably lowers our emotional and mental well-being. We are not in a position to decide that we know better than parents what their own young children need. It would benefit you to move away from this type of thinking. It doesn't serve you positively. Instead, a better focus in all of this is to deal strictly with your own reality. Your son wants contact with you. Your son maintains contact with you. This is so much more important than any personal anecdote on the internet from complete strangers.
I do realize after reading many confusing posts from you across various threads, professional help would be a great avenue to help you cope with all of the trauma you've experienced. It can help you to see other perspectives more clearly. These two things can lead to more positive interactions with your son. You cannot control him, but you can control what you initiate discussions on. As a mother, I genuinely wish peace and reconcilliation for you. Truly, I do.