Idealism and duct-tape- they are holding the world-view together..
Specialisation always was this species strong point. Acceptance that the user might have his strong-point elsewhere and is so nice as to not harass you with his worldview. Imagine if you went into your local bakery, and there behind the counter stands a guy all in white:
"Good morning. Try our donuts today. You could make donuts too. Its easy. Come on ill show you. And then you will be self reliant when it comes to donuts. There are thousands of great recipes online - okay, some are broken, but you dont get to become a expert in donut making - without giving a little bit back..
Sir, Sir - you forgot your Donuts. Maybe he is diabetic and forgot - or evil cooperate donut buyer - or the one dough ring to bind them all is too much of a power.."
With great specialisation comes great loss off understanding on other parts of your life.
There are way too many decisions we need to make in this world to really be informed on every one. Of course, in our world, understanding software and safety is in our scope of knowledge, so we believe everyone should have it. However, not everyone is in our world. I am sure tech people make all sorts of uninformed decisions in other realms that people in those fields would be appalled at. It is OUR job to help protect regular people who don't have the time to learn our world be safe, just as it is the job of those other fields to help keep us safe.
Heaven forbid. The unaware, uninformed user is the bread and butter that the Internet businesses survive on. Tech-savvy users are bad bad bad. Protected, gullible users is what keeps the engines running.
The choice isn't prevented. There is just a small barrier put in place of the choice. Installing a different version of firefox is not difficult, but it makes sure the user is absolutely sure, and helps get an idea across of the ramifications.
This. Most of the people do not care about this stuff and they do not wish to learn it. Also, like with vaccines, it is important that sufficient number of people are protected for the malware/viruses to not spread.