Switzerland is like that. I remember asking (in my best German) the person manning a ticket counter at Zurich train station if they spoke French once, if a look could kill I'd be dead, lol.

It gives the strange feeling that although they decided to create a country together they don't want to interact with each others unless absolutely necessary.

That's not it. Everyone in Zurich studies French at school, if you speak slowly to them in French, it's pretty likely that they will understand a lot of what you say (if they are familiar with the context of course). Similarly, if you speak slowly in German to a French-speaking Swiss, it's pretty likely that they will understand a lot of what you say (again, if they are familiar with the context).

It's just harder to speak in another language than to understand it, so if you ask someone to speak...

Next time, ask them if they understand French :-).