The only reason I'm comfortable transmitting sensitive over the internet is that we've got a bunch of proven systems like "encryption" that can guarantee my ISP, etc. doesn't learn much about my actual traffic.
Fundamentally, if you're giving an application your passwords, it is precisely so that the application can transmit those passwords, in full, to the relevant services. If you don't trust "mathematically proven safe" then it's already unsafe - and it's unsafe to a ton of third parties used to route the internet.
It's important because that means this is a harmless issue - there's a linked 3rd party mathematic proof by a credible authority on security (CloudFlare), and other password managers have similar features.
"I'd like clearer documentation" is still a reasonable request, but I don't think the OP is at all justified in acting like this is some outrageous trespass.
If you care about a harmless issue this intensely, you should be taking some responsibility to actually inspect the code. Given there was a feature flag to disable it, even a cursory scan with a cheap LLM probably would have found the "issue"