While I do a lot of PuGing myself, I must disagree quite a bit with your first point:
Having something on a schedule and fun are not mutually exclusive. Having a regular raid night and time is no different from joining a basketball league, planning D&D nights, or setting aside a night each week to get together with a certain group of friends.
When I plan my raid night on Saturday, I’m effectively placing “fun” onto my calendar for three hours.