Unless you have a boss telling you to support IE6, you don't. People need to stop using this prehistoric excuse for a browser.

As you said, some people work at companies that mandate its use - they have no choice. While that's happening, it needs to be considered.

If by no longer supporting IE6 we can force these companies to finally go with the times, then by all means, no, we should not consider this. We cannot endlessly cater to every outdated technology ever.

Besides, these companies have absolutely zero valid reasons to keep using this crutch - it's severely outdated, a giant gaping security hole and a hindrance to the entire world wide web.

And no, legacy applications built upon IE6 on which some corporations have based their entire internal communication (or other things) are not an argument for supporting IE6, but instead gives us all the more reason to force them to get rid of it.