That's an interesting observation. It's likely due to how the interaction was coded when Silverware Golem was first released. Back then, there was no way to buff minions in your hand as a warlock. So to simplify the code (and keep it clean), they probably just summon a copy of a generic Silverware Golem card rather than try to create a code that plays the card you discarded (which would be much more complicated). Yeah, it was short sighted to do it that way, but I dont blame them. The simplest codes are always the best codes.