I can assure you that I do not personally care that people use Uber, but that's neither here nor there. What you describe is not a network effect; it's true of _any_ business you want to see stay in business. If I liked shopping at e.g. Walmart, yes, I would implicitely want others to shop there as I don't want to see them go out of business. That doesn't mean I'd have a second thought about switching to a competitor if they provided a similar service at a lower price.

FB is successful because no one I interact with is on a different platform. They same is true for them, so we all stay. Network effect.