If you have multiple servers for redundancy or simply for different products everything will go down if that target area is hit. By being hit it could be an engineer spilling coffee over that rack, earthquake, powerouttage, fire etc.
It's pretty much the same as putting all your eggs in a single basket.
I don't see whats so dumb about having completely different services running at the same location..
Yeah, running 2 irc servers in the same location would be dumb, but running 1 forums/web/irc server, and 1 ut server, theres hardly any difference whether you run them apart or together, its not like chances of either of them going down are smaller.