Is your writing your ‘letter to the world?’ Why? How?

I cannot go as far as to say my writing is for the entire world, and I wouldn't describe it as something so frigid and serious sounding as a 'letter'.

Thinking about this question, I can't help but reflect on Emily Dickinson's writing, and how her situation supposedly shaped her poetic voice.
Because of her particularly idiosyncratic style, only about 1% of the 1,775 known poems she wrote were ever published. Publishers would demand re-edits that detracted from what she was attempting to portray, and there's little doubt that a fair few of her poems would raise an eyebrow of concern, e.g. 324, which criticises the need to go to church in order to be saved. Considering her heavily Christian surroundings, this would have been considered scandalous.
We can conclude that this was not very much of a deterrent for her work, and if 709 is anything to go by, it acted more as inspiration:

Publication - is the Auction

Of the Mind of Man -

Poverty - be justifying

For so foul a thing

It wouldn't seem like she was writing for the public interest (as the phrase 'letter to the world' would suggest). It seems to be more about allowing her creativity to occupy a place within the world. After all, what is creativity if it is not manifested in some way?

I liken my own creative efforts to this. If I had to come up with a metaphor to describe it, I'd call my work a sort of platter submitted for the approval of those around me. Any 'message' could be considered a 'fortune cookie' on the side. A bonus to the bulk of the meal. Make of it what you will, but don't feel like I expect you to meditate upon it.

I suddenly feel really hungry for some Chinese food...