In the case of Atom, they state quite plainly on first-load that they track usage for the purposes of telemetry/product improvement, and you can opt-out on first-open.

I'm not really sure I see the issue?

Also, usually with Google Analytics you're viewing a remote website (or in this case I suppose you're phoning home for updates on every startup). If they really wanted to, they could just check their webserver logs. It just saves them having to parse it or graph it.

Is there some particular new information you're concerned or worried about leaking, that they don't already have?

Then how did you know about it? (sorry, I had to). Seriously though, everyone knows most web pages use GA.