Offtopic, but I used to think that too until a coworker I'd never met emailed me using that address, warning me that apparently the proxy had cached my view of my profile page and he was able to view it. Has this been fixed yet?
Whatever you do, there will always be a non-trivial number of ISPs and company networks that have misconfigured proxies that overzealously cache sensitive data and display to everyone with not a care in the world.
Your system is setup to ask your corporate proxy to fetch unencrypted pages for you. That proxy may be configured to make a physical printout on your boss's printer of every page you request and there's nothing YC can do about that beyond offering https://news.ycombinator.com/ for you to use. That, too, may not be sufficient if your company has its own trusted SSL cert installed which is used to proxy and intercept everything so that all your internet activity can be decrypted.