Hacker News Reader

I know (well at least internet sources told me) he worked for a government agency in France similar to NSA in USA.

Probably still is, and netgem is his cover.

Why would he need to cover up that he is working for a government agency?

Considering that you apparently aren't fooled by that cover up, it can't be that much worth anyway.

The idea is anytime someone is on to him, someone like you will counter-argue, giving him the perfect cover.