Agreed in general. But: this form asks for your email address, if you post from your corporate IP the company is known, if you add in all the rest of the data then the company might identifiable as well, if you have posted stuff in fora from your email account and tied it in to your corporate identity then that can be put together. After all, how many companies with between 'x' and 'y' employers in such and such an area making profit with a market cap of 'z' have active members on HN.
You're not nearly as anonymous as you think you are and this is very juicy data.
On the whole transparency is a good thing but this is probably not the best way to go about achieving it.
A lot of university hiring offices collect this level of stats (although in less useful form) from recent graduates, and often republish.
Post from home, use a throwaway email address or at least a gmail-type address vs. @palantir.net work address, is probably enough. The most personally detrimental leak would probably be "I work for Yahoo and am currently interviewing with Google and Facebook" vs. that Google and Facebook extended specific offers, and in that case, you're already trusting the HR departments, recruiters, etc.
You're not nearly as anonymous as you think you are and this is very juicy data.
On the whole transparency is a good thing but this is probably not the best way to go about achieving it.