They're fine with it now. They won't be, when the next potential revenue source on their list is to crack down on it.
Remember, revenue must always increase, and must always increase faster than the year before (and this is more important than keeping the company alive), so companies always try increasingly desperate measures. Right now they are nowhere near the point of that particular measure. But they will be in the future.
[1] https://tailscale.com/blog/tailnet-lock-ga#self-hosting