Answer: It lets the reader share in the feeling of fighting for a historic cause through years of frustration, uncertainty, and victory.
Explanation: For all the people who just put random answers that don't help out at all, I hope you stub your big toe multiple times today. Your librarian did not put a women's history book in the fiction section. Your humor is stuck in 2018. And to the dude that answered this in a different post that just said "what do you mean", just don't even answer the post at all. Do a comment instead. So heated over this.
Hester means that the letter has been on her for too long and too many people have seen it for it to just be taken off. The damage the letter has caused her has already been done.