Damn, man. A little understanding or sympathy? I'm sure he's just a bit out of shape and he can't vent about his dog dying, so he's venting at the situation. Anyone can understand that. And if you can't, at least try not to be quite such a dick about it. I don't know why you seemed to take is so personally, but I'm sure it wasn't personal slight.
That being said...
Having first hand experience with vet clinics, ie; personal experience, working at them, very good friends with multiple vets/owners, and having been involved in 'behind the scenes' buying/selling for a vet clinic, I'm well aware that many of them overcharge. Not all of them, many of them. One of their favorites ways to do it - innoculations. Most of your dogs innocs are not needed as often as they used to anymore due to changes in the innocs. However, they still continue with the same rules of innocs as they've always had. I won't go into this any further as it varies from place to place, doctor to doctor.
I will tell you this, don't be afraid to haggle with them. You'd be suprised at some of the discounts you can get, etc if you're hurting. And for my dogs, I don't mind doing it if it'll help.