That's just what you do though, isn't it? When you're making music I mean... write a bunch of stuff and then title it afterwards. I mean yeah, sometimes you do set out with a clear image in your head and try and write "to" that, but most times you just flesh things out and see where they end up. Especially with instrumental music, but think about non-instrumental music for a sec, most of the titles for that is based off the lyrics and the lyrics are usually the last thing you do anyway. I know most of my stuff has working titles, and only gets a final title when its near finished or if it has lyrics, takes a title from that.
Some of Aphex's titles are a bit more trolly, but I think even that's a reaction to the pointlessness of giving stuff like that a title... the more abstract something is, the less sense it makes to call it something "normal".