thejilyship:

I don’t really think these two things are comparable, strictly speaking. I mean, they both hurt her of course, but they weren’t the same thing?

Petunia and Lily’s relationship deteriorated over a long time, and they went months without seeing one another and it probably hurt differently because your family is supposed to love you unconditionally. To have  your parents accept something wholeheartedly and then have your sister talking about it with disdain and derision had to hurt a lot. But it was a private kind of hurt, something that she dealt with when she was home, the consequences, while awful, were contained to herself, her sister and her parents. It was an ongoing thing, there was no final moment. 

However, the fallout with Snape was very public and there was a final moment. There was a lot of build up, but when he called her a mudblood, it was in front of half the school. In the middle of a war. Where muggle borns were being killed simply for their blood status. This is a different can of worms entirely with a whole lot of implications and consequences. 

The people in Lily’s life hurt her, and I think that was one of the reasons she made sure that she was ‘there for [others] when no one else was.’ She knew how it felt to be treated poorly, and I think she made sure that she never made anyone else feel the way she did.