Is it possible to delete your account and automatically remove all your posts, or when you remove your account do your questions/answers remain on the site?
Your question is blossoming into five or six separate questions. I will attempt to run over most of them quickly:
You can delete your account but your posts stay.
Your posts will be attributed to deleted version of your user. This may keep your name, it may be attributed a user1234566 account. Probably the second (I think it's only cross-site question migrations that used to throw the name over).
Editing is an essential part to maintaining a system like this. People go missing and abandon things. This way everybody can maintain everything and that's not going to change.
Edited posts have a revision history that anybody can see. They're not putting words in your mouth, they're putting words in your post and people can see evidence of that.
Getting upset with a system and wanting to leave is not a phenomenon unique to us, or even the Internet. You see it in most mammal communities and it has been an essential part of genetic and societal development for hundreds of thousands of years.
That said, we want a happy community here and we try help that end by being completely open from the offset. If the community and the moderators fail you, there are also people at Stack Exchange you can talk to... But none of that will ever stop people becoming disenfranchised. We could dip into this well but you've already said you've little interest in the psychology of things.
If you have a specific grievance, we want to know about it. This is particularly relevant to me because I was the person who dealt with one of your questions yesterday.
You can ask Stack Exchange to erase your account following the methods posted on all the previously asked question in meta about the same subject.
No, the posts that you created with your account are property of the Ask Ubuntu and the Stack Exchange network, even if you ask them to be deleted or removed when your account is, they will not and you cannot do it just because you want to. Their content is part of the site when you create them and will not be removed when your account is.
This all question is a dupe of many others around the site, the reasons are always the same... Drama, user feels that he is not appreciated or targeted by evil cat like creatures and wants to leave and remove his account and destroy his/her contributions.
From what I understand this is over edits? Really? Look, take some time for yourself, go for a walk and enjoy the sun, come back when you want to (or not, no one forces anyone to be around, ever). There are many more things to worry about in life; edits on a website that allows and stimulates them is not one of the things that would make me wake up in the middle of the night.
If after you walk you still feel upset about anything then just ask the Stack Exchange community to remove your account, it's fine, but your posts stay.