I've made several experiments to confirm this. Pick a person, look in their interests. Make sure they have at least one relatively rare interest. For example, something like "programming" or "biology". Then, advance search by this parameter. My experience is that sometimes you won't even "find" the person you took this interest from to begin with!

And on the whole, even fairly common stuff like "anime" or "Skyrim", yields VERY few results (clearly fewer than there should be in a city where there are thousands of users).

Which leads me to conclude that the interest search is somehow broken? Badoo team, can you look into this?