The one I visited had just such a sign posted at the entrance.
> Customs and immigration officials everywhere ask probing questions to catch smugglers and criminals.
I've never been asked such questions by customs in Australia, Canada, France, or the UK. The only ones who gave me a harder time were the American customs officials, as I was re-entering my own fucking country from Canada. They couldn't even be bothered to smile or act polite.
For good or ill, Japanese trust of foreigners is much lower than in the Western world. Maybe they loosened up a bit since 2011 but they're tightening back up now what with idiot streamers gaijin-smashing into construction sites and the like. Racism and open discrimination against people who even look foreign is higher than what a Canadian or Brit would be used to. Given that the Japanese are more interested in preserving their culture against foreign influence than the Brits or Canadians, it makes sense, yes. But it still felt dystopian at the point of entry. Once I'd cleared that hurdle, though, I had a great time in Japan and most of the people I met were pretty laid back.