Aline is a bit of a Hacker News legend. She's been active here for longer than most people have been working and when you see how she's built her product, it's plainly obvious that she legitimately understands and sides with the HN community.

I bet the genuine answer to your question is that she knows it's a resource that could help tons of people (at a time when tons of people need that help) and paywalling it means that it won't serve that same purpose.