He can feel however he likes; nothing compelled him to post it publicly for all the world to read and comment.

> How could someone be resentful at losing their job to a nonsensical decision making process? How could someone possibly be frustrated to be shown zero gratitude for their very profitable work for someone else?

He chose to work for Mark Zuckerberg. He wishes he could continue working for Mark Zuckerberg, in order to make Mark Zuckerberg richer. Perhaps you can understand why I don't have a lot of empathy.