Wherever you see the "login with facebook" button, you have FB tracking you. This is why lots of people avoid sites that have this button. It adds very little and puts a lot of people off. Why keep it around on an OSS project if it's going to do nothing of real value and will put off both users of the CRM and people who would like to host a CRM but don't want the FB affiliation?

I get that you might like it, that's fine, but it's not serving any good purpose here. Google login would be more widespread if you must have a 3rd party button. Yes, Google track as well and yes, that's also going to put people off, but if you feel the need to have one at all, get a more useful one. Or better yet, remove them all, have local user registration and put a hook in place for developers to plugin other buttons using different contrib repos. Then you can have both without polluting the core project with 3rd party deps.