Mais la, there are many different ways to prepare gumbo. Or variations of gumbo. Par exemple, there is chicken and sausage, seafood, oyster, shrimp and collards/crab, duck and andouille, and gumbo z'Herbes.
The recipe you linked was specifically for seafood gumbo which Monsieur Besh does call for the use of tomatoes. The recipe that does call for the use of tomatoes are his version of gumbo z'Herbes, which is a somewhat vegetarian type of gumbo that some refer to as "Green Gumbo".
A few years ago Monsieur Besh had sold a special "hometown edition" of this book
I got a copy of it, as it was limited edition, when he was doing a book signing at Mary Lou's Book Sack.
In this special edition he also had a creole-style gumbo that used tomatoes that was more like a seafood gumbo than a green gumbo.
So, to answer your question, OUI! Monsieur Besh does use tomatoes in his gumbo, but not all the time.