If you're at a higher end restaurant the burger is a way to put a cheaper, accessible option on the menu. It's there so that a party of 4 or more can show up and someone who's more price sensitive or less adventurous can still have a good time. (Roast chicken and an entree salad serve similar purposes.)

If it's an insult from the chef, that's pretty bad. Extremely snobby to put it on the menu without putting effort in. Burgers are good and a kitchen can outsource the only hard parts (baking a great bun, and grinding the meat) to their suppliers.