Why boycott Libra? Let it promotes cryptocurrency to the masses. Mass adoption is good for us. We don't have to use Libra, we can still use Bitcoin and no one can take it away from us.
We can't dictate users to boycott Libra. What we can do is educate those fb users what Libra can do to their lives and the pros and cons of using it. Also, the introduction of Libra to masses might really create massive adoption of crypto. And then later on, they will learn more about crypto and the benefits of bitcoin over Libra. Let them decide what they want in life.