Obviously someone at Zoom thinks they get value out if it. But that's quite different from "this is a revenue source", which would suggest Facebook paying money for it. Your typical company will happily put a tracking SDK in so some marketers get some more graphs to look at in Facebook Analytics.

How do you know if it isn’t a revenue stream?

I guess I’m thinking that if this information that Zoom (a publicly traded company) was doing this, it would be bad for business, so doing it just optionally for fun, seems like all risk and that an appropriate reward would be a financial incentive.

Even if it isn't a revenue stream it can still have value to them, it doesn't have to be for "fun". This may simply be one of their ways of acquiring metrics.

As for it not appearing in their TOS, the "risk", it isn't unusual for the left hand to not know what the right is doing. Those drafting the legal text may not have known that this particular analytics system was being used.

There are many arguments for why this was overlooked, and why it exists, without it having to be direct revenue.