Jazz is not Blues and Blues is not Jazz.......

two shrinking genres (as wonderful as they are... that is the reality)

commercial decision to clump together

With respect, I think some of you are missing the point. If you listen to the best Jazz radio stations (WBGO, Newark, NJ for example) they play a great deal of Blues. I’m not sure what exactly the OP means by “some internet sites” being offenders, but Blues and Jazz are intertwined both historically and stylistically; in a way, inseparable and, yes, overlapping. I can’t speak to what “sites” the OP refers to, or whether their motivation is commercial interests, but I can tell you that there are many very musically legitimate reasons for “clumping” them together.

Each to his/her own, and freedom to like whatever one likes.  But like country-rock, "lite-classical,  and other hybrids...some may like and some may not.  As much as I like B.B. King, I do not consider him Jazz and I do not consider Paul Desmond Blues. and I do believe that singers blur that line more often...like Ella and Dinah Washington.  

Have fun, enjoy what you listen to ...even if that is Ernest Tubb. 

I’m actually confused about what exactly the issue is. First it seemed that your objection was to the way some blur the lines when naming the various genres. Not sure how that has anything to do with liking or not liking certain artists or certain genres. Why get hung up with strict definitions? I don’t understand comments like “I don’t consider Paul Desmond blues”. Desmond was a lot of things. He played, at various times, West Coast, Cool, Swing, Ballads and, yes, even Blues sometimes.