I don't disagree that it's possible to configure Firefox to respect your privacy. I myself use it sometimes and have a similar configuration.
But it is extremely misleading for them to be shouting "privacy" at every opportunity while the truth is that their browser leaks personal data like a sieve in the default configuration. This would give a false sense of security to non-technical people who don't have the skills to see through these lies.
I get you about the updates. It's a risk-reward ratio I accept because firefox + noscript + always starting in a private session is way more helpful than the update problem is harmful. Using a VPN a lot of the time helps, too. There is no solution I know of that is perfect. My threat model is pretty relaxed, though, so what I do is mostly for my peace of mind. You have reminded me that I should start spoofing my user agent again.