Calling Michael Buble a Mel Torme tribute act is supposed to be an insult?

Mel Torme was extremely talented, both as a musician and as a songwriter/composer.   Bublé isn't a "tribute act" in the sense of just doing covers of Torme songs, of course. And I'd say that even when he does "cover" the songs of crooners like Sinatra, Dean Martin, Carmichael, etc., he puts a more contemporary stamp on the arrangements.   (Compare Bublé's "Sway," for instance, to Dean Martin's.)
Plus, Mel Torme is no longer adding to his own list of compositions and Bublé is writing some of his own. So I'd say it's more a matter of Bublé carrying on the growth and evolution of the jazz/pop music of the '40s, '50s and '60s. Not quite the same thing as a purely "tribute artist."