It depends! Does it?

For some reason, I really resent it when people, especially at workplace say "It depends!" with an air of knowing!  

What does that mean anyway? It doesn't in the least answer what you are asking. For example, the other day, we asked someone does a door-to-door health intervention (spraying anti-malarial insecticides on walls of houses) - How many houses do you cover in a day? 

"It depends" came the answer.

"On what?" I persisted!

"On many things like the size of the houses, the number of rooms, the type of walls, etc".

This type of an answer helps no one. But sadly, lots of people talk like this!

He couldve simply said " Around 10-20, depending on the type of houses".

I really don't get why people cloud things - why they settle for being ambiguous and obscure where they can be a little more objective and say something concrete. Its almost as it is either:

1. They don't know

2. They don't want to tell you

3. They want to make it seem like its something complex when it is not. 

4. Its too big a load on their brain to think about it and come up with an answer.