The Grokster versus Smith & Wesson argument

Some things in law never make any sense. Take for example the whole debate on Grokster. RIAA/MPAA won against Grokster for creating a technology that supposedly empowered people to infringe on copyright. We need not go into the good of peer-to-peer technologies and how it takes a lot of the burden off of Internet providers and servers by using the populace as an uploading mechanism.
While in the similar context, the Supreme court decided a while ago that Smith & Wesson cannot be sued for people that murder with their products.
So here it is in a detailed diagram.
GROKSTER -> P2P -> USER -> USER-ILLEGAL-DEED -> GROKSTER LIABLE
SMITH&WESSON -> GUNS -> USER -> USER-ILLEGAL-DEED -> SMITH&WESSON NOT LIABLE
Go figure. Talk about inconsistent.