That sounds more like Canonical marketing-speak, than Mozilla. My guess would be that it is Canonical who approached Mozilla for snap support, and Mozilla said yes.
Meanwhile, Mozilla still maintains ppa (mozillateam) with apt version. There's also Flatpak version, which delivers what snap promised.
If someone (Ubuntu) wants to package and distribute free software (Firefox) in their own format (Snap), the upstream maintainers (Mozilla) shouldn't hinder it no matter how bad the format is - it's not their job.
People are free to distribute Firefox however they want... Without the logo and Firefox branding. If they want to distribute it _as_ Firefox they have to meet Mozilla's conditions
