I'm not sure it's fair to dismiss Steak Tartare simply as "seasoned hamburger." Here's what Irma and Marion wrote in the '75 Joy of Cooking:
STEAK TARTARE OR CANNIBAL BALLS
"We always tender this recipe with some misgiving because of the risks run in eating uncooked meat and egg. Cannibal balls are a mini-version of the classic Steak Tartare or Cannibal Mound: a clump of raw beef with a shallow indentation on top into which a raw egg yolk is broken, garnished with chopped onion, caviar or anchovy, and capers."
They then to into their recipe, which specifically calls for top sirloin, not just any ground beef. (Fat ratios are different from cut to cut; top sirloin is quite lean - think of it as tofu that tastes good!)
Michael Lomonaco, in the days when he was chef at the 21 Club, noted in his The '21' Cookbook that "Dinah Shore, the embodiment of grace and femininity, requested it every time she came to '21'." In his recipe, he notes that the meat should be ground as close to mealtime as possible. He does season the meat, with Worcestershire, Dijon, Tobasco, chopped egg whites, red onion and shallots, plus the traditional anchovy and some parsley.