Until this moment I had no earthly idea you could join a Zoom call from a browser. Good on them for their evil genius design team :-p
"Zoom's forced app is irresponsible" - https://shkspr.mobi/blog/2020/03/zooms-forced-app-is-irrespo...
Shady patterns mean shady company
A lot of these kinds of dark patterns sacrifice long term user satisfaction and brand reputation for short-term gains in questionable internal metrics (metrics that are often tied to bonuses for people who couldn't care less about the long-term success of the company or its customers).
It's just WebRTC, like Google Meet, Jitsi, etc.