The thing with an analogy is that you say one thing to illustrate a larger point about another thing. Nobody uses TOR to keep their email password safe. To be honest that doesn't even make sense.
Here's a better analogy though this is getting away from the main point that the FBI knowingly distributed videos of children getting raped in order to blow a case.
Everything you do on the internet has the ability to be monitored. Every password you type, every site you visit, every credit card number you enter, every Facebook status update. All of this can then be kept in a file to build up information on you. In fact this already happens - on your computer right now are various pieces of information called tracking cookies; these track you across various sites and are mainly used by advertisers to show you adverts which they think might be interesting to you based on your web history. This is a simplistic example but the same applies on a larger scale. People's lives are connected to the internet now - from a simple email address you can potentially find out people's life history, pictures of their kids, what their postcode is, what credit score they have, bank account details.
Now I don't really use TOR because I use a different form of technology that suits my needs better however TOR is designed as a technology that encrypts internet
traffic. People think that the only people who view traffic are Governments - this is demonstrably wrong. Sky customers will have recently or are about to get an email telling them that their services online have now been restricted. They have to opt out of parental filters for their internet. TOR bypasses this filter in the same way it bypasses filters in every censorship regime on the planet.
So let's give a scenario. Let's say that me and you are doing a deal to purchase some technology. I'm in Manchester, you're in Beijing. We now have a problem that our communication can be monitored by the US Government, the Chinese Government and the British Government. Maybe we're selling a technology that will massively undercut a Chinese firm's profits? Maybe we're fleshing out a deal in secret and the Chinese are noting down every figure, every proposal and every detail of our deal in order to pass it to their state industries which denies us not only our millions of pounds of profit but scams the UK out of all that new industry.
Which is something that has actually happened on numerous occasions. TOR completely prevents this.
Let's say for example that you're a private citizen who has strong political opinions. Let's say that one of your political opinions is that something your Government is doing is wrong and immoral and you blog about this to try and change it. On a monitored internet system, the Government can take over the blog, alter it then walk in and arrest the author for anti-State posts.
Which again is something that has actually happened on numerous occasions. TOR completely prevents this.
Let's say that you're somebody interested in computer security. One of the things that major firms offer are "bug bounties" or "ethical reporting procedures" if you find holes in the security of the system so that you get rewarded and they get to fix the breach without a big kerfuffle or having it leaked online. So you diligently find a hole in a Facebook system and report it to them, hoping that they'll fix the hole so that everybody is safer but Facebook tracks down your identity and has you jailed.
This is something that has actually happened. TOR completely prevent this.
You say "oh well I don't need privacy" but this is as stupid as saying we should cancel the NHS because you're not sick. You don't fight for further privacy legislation because you personally need it, you fight for better privacy legislation because it's a public good and
privacy is a fundamental human right. The people who require privacy legislation are the people who keep you from the gates of fascism because they're the ones who report on Governments overstepping.
Every citizen should feel comfortable to have freedom of speech unmonitored by their Governments.