last I checked, firefox doesn't download AI models unless you try to use a (clearly-labeled) feature that requires them. you can also manage/uninstall them at about:addons

https://support.mozilla.org/en-US/kb/on-device-models

totally uncharitable interpretation of the quote linked here aside, how is providing an interface for using fully local models not user first software?

If the users don't want the feature, then pushing it on them is not user first. It's that simple.