if a person's writing something purely as an outlet, for their own eyes, i'm not sure why they'd choose to post it publicly.
when they post something out there for others to read, isn't it good manners to try and present it in its best aspect? if i want others to read my writing, crit or comment on it, why should i expect them to spend their own precious time on it if i can't be bothered to look for simple issues like typos?
most my poems spill out pretty fast, minutes... but i'll edit and re-edit as i read it through on word/notepad. when i'm relatively happy with it, i'll post--but generally looking for critique with an eye to making improvements. if i'm happy with it as it stands, i may not look for crit but, at the same time, keep an open mind to changes in the future. too often i've had material published in print only to look back on it, years later, to realise its weaknesses.
hell, i've gone back and read stuff i wrote decades ago and might spot a way to improve it, so it'll get an edit.
as for here, and other websites, i may have edited till i think it's 'right', hit 'submit' only to notice a glaring typo or mistake where i was swapping stuff in it about. and then i go RIGHT back in and edit it to make it right!