I have made burgers hundreds if not thousands of times and I have never done more than roll ground beef into a ball ans squish it flat. Salt and spices are completely unnecessarily, who am I, Gordon Ramsey? Sliced onion on top of the patty does plenty of work.

You are comparing a prepared product to a raw ingredient. Raw beef is pretty boring which is why every single restaurant add some combination of salt, pepper, mayo, ketchup, mustard, oil, butter, gochujang, etc to make it into food. If you want to convince the world to eat unseasoned beef and onion burgers be my guest but you have a tougher hill to climb than the vegetarians. Eat what makes you happy, but maybe acknowledge it's not actual cooking.