I think a lot of it is that everyone has heard of Zoom, and Zoom works pretty well for calls with a lot of people, so it became the default for group video call

I think a lot of it is that everyone has heard of Zoom, and Zoom works pretty well for calls with a lot of people, so it became the default for group video calls. The “UX” in this case was “fixed” by being less crashy than the competition for long enough to earn a reputation. As someone with a security background myself, I really hope organizations use it less and less, because the competition by now works just fine. But as a human living in the world, I don’t refuse to use Zoom, I just use it on my iPad and assume the conversation is intercepted somewhere.