Probabaly the reason why blues players are seen as more soulfull is because its a lot easier to do a big bend while closing your eyes and generally getting into the sound then it is to shred. Shredders are somewhat limited to how much freedom they have to "get into it" since they have dedicate themselves mentally and physically to the demanding techniques they're performing.

I never agreed with those who say shredders don't have as much soul as blues players. Everyone has a different type of music that sends chills down their spine. If you enjoy what you're playing then to you that music will have the most soul.

But I suppose for the vast majority of the population, its easier to find "soul" in, say, B.B. King's playing then Yngwie's, simply because they can digest it better.