Another view point. When you talk face to face to a person or a group of people, once you say something it can’t be edited or deleted. Although a face to face conversation flows at a much faster pace than typing a post online. Not having the ability to delete or edit may make people think more before pressing the send button. You have the time to do so. 
I am still open minded about having edits / deletes.  

 A passing conversation isn't a permanent record, though. Aside from memory, it's not stored ad infinitum. Moreover, if abuse/harassment occurs, such as the canceling thing, it boils down to hearsay.

None of that is even remotely true without edits and deletion.

Transparency for governments, corporations, money and software. Privacy for the people.  

 Good points. Thank you. I do think that more thought before posting would be a good idea for many. Absolutely agree,  Privacy for the people.