The description PG gives of 'the ideal cofounder' tends to be someone who you've known for a long time, or have a fairly 'deep' history with - you're good friends or colleagues who get on really well or something like that.
If you go by that definition, you simply cannot 'go out and find' someone because it would then take years to reach that level of comradeship.
But that doesn't mean everyone who didn't have a technically inclined college experience and doesn't have a hacking job should give up on the whole concept of cofounders.
No - there are plenty of places to meet that sort of friend. The key point is not meeting people at college or at a job, but rather to know someone very well in order to be prepared to go through thick and thin with them.
If you go by that definition, you simply cannot 'go out and find' someone because it would then take years to reach that level of comradeship.