I think you did the right thing too, working at a vet clinic I see the results of people not de-sexing their pets constantly.
It might be because they seem to think that removing his testicles make him less of a male (rubbish, are you trying to tell me that those poor ladies who lose a breast through cancer are less of a woman?!) or because of the "couldn't afford it" excuse. I find it ridiculous that you would ignore your vets advice after reading Wiki!
Searching anything on the net will bring you a opposing results at some point, penicillin is fantastic but look long enough and you will find that people have died from its use.
Unless you plan on breeding well breed dogs responsibly, de-sex.