blues: slow playing, lots of feeling.
shred: fast playing, lots of technique.
Seeing that this seems to be the case, this just seems wrong. Everybody that plays anything resembling a musical instrument would need both to master it. You can't play with feeling if you have zero technique, no matter how slow.
My suggestion is to ignore the terms "blues" or "shred". It's useless and as you can see, confuse you. Just learn the techniques, learn the music theories, and let other people worry about the classification of what you're doing. If the technique you want to learn is in "shred" territory, then so be it. If the scale you like is in "blues", then by all means learn it. Don't be over concerned if what you end up doing is actually "jazz".