Not to retail workers. The vast majority of them are underpaid and overworked. Between the stressful nature of a job like that and the various stresses that tend to come along with being an adult working for anywhere near minimum wage they probably don’t have the mental bandwidth to care about anything beyond their ability to get by. You’re not going to change anything by being a dick to someone like that.
Now if you happen to run into a developer or similarly paid person for a company like Meta or Google, absolutely be a dick to them. They’ve chosen to work for evil and have the means to choose otherwise. Acute social pressure could actually make them care and choose something else.
Mull at least has been fixed in the divestOS repo. I can’t speak to fennec as I don’t use it.
The version in the f-droid main repo is behind because of Mozilla changing their repo system thus screwing with the build process and at least for now currently requiring a compiler that doesn’t meet F-Droid’s (IMO slightly ridiculous) standards for allowable software.