I was shocked when I first got there as well to find out they didn't drink squash.
Anyone who puts the squash in first is an eejit. Clearly the correct method is to put as much water as you want to drink (controlling capacity), and then, in a separate action, add the squash until the drink is precisely the right colour (controlling strength).
If you do it backwards, then you are unable to isolate the separate adjustable elements and your ability to accurately control the quality of your glass of squash is dramatically reduced. Some people have no self respect.