Re: What's the concern?
I presume the concern is that the voters did not necessarily give permission for this information to be given to anyone, without restriction -- or audit.
Privacy is not one dimensional: I really don't mind the UK secret services knowing what I use my VPN for, but it doesn't mean I want the council's parking control officer to know; I don't mind the latter knowing my address, but I don't want him to know my date of birth; etc.
There is also the issue of aggregation. Sometimes secrets that aren't even in the data can be given away by the data (e.g. a geographic clustering of security cleared people in a rural town). Databases which contain gender and D.o.B. information can be used to identify the locations of thousands of young women, for instance.
However, the key flaw in your argument is to assume that everyone else should be comfortable with your own personal privacy levels. I post here using my full name, but I don't expect everyone else to, and I'd be highly unimpressed with someone "outing" a fellow commentard who had used a handle or posted AC.