I don’t think anyone is saying Firefox is inherently bad. What I’m reading, and what I believe, is Google just has a better product for secure enterprise browsing because of the controls they offer

The browser is where basically all your work happens, especially as a Workspace customer—think about how much of your work is done in the browser. That makes it a huge, attractive attack surface. And attackers don't even need a browser vulnerability; they can just convince an employee to install a malicious browser extension, and suddenly they can steal passwords, watch everything you do, and hijack your sessions on other sites.

So security teams need visibility into what's happening in the browser. Google does a decent—not great—job of providing this through Managed Chrome: centralized logs, control over which extensions can be installed, even alerts when someone reuses their Workspace password elsewhere.

Firefox, Safari, and most others don't offer these business controls, which means a security team allowing them is flying blind. And a blind security team is gonna have a bad time… mmmkay.

On support: someone mentioned using Firefox to verify their app works across browsers—god's work, truly. But not every vendor does that, so IT ends up fielding "this site just isn't working" tickets that turn out to be browser compatibility issues. Fewer supported browsers means a smaller surface to support and a better experience all around.

This can't be enforced where you're not using your corporate identity. A Dropbox account on your personal email is still accessible from any browser.