I think it's perfectly reasonable to have multiple reasons for doing something. Making money and deterring malicious users are both valid reasons. Some forums have paid fees for the purpose of deterring unwanted users (MetaFilter, Something Awful, Bitcoin Wiki in the past), so it's certainly a strategy with a precedent.
Yes, you can have as many reasons as you want, but the more you list them off to the public, the more time you have to spend defending them individually.. was the point that I was making.
There is a damn good reason why good PR people often refuse to comment. People remember stupid responses, but forget that “Zoom declined to comment to this article” very quickly.
Zoom needs a business model and saying "if you want encryption you need to pay for it", to me sounds like a reasonable approach to making money.
Once you start dragging other reasons into it, you need to start defending them.