You're not wrong, but that's the price for being the market leader like WotC is with D&D. People will confuse similar products for yours because they know your name. Growing up in the 80s, parents would say their kids were playing Nintendo even if they had a Sega or Atari game syste. Any person I've ever met from Texas refers to any form of soda that isn't a Dr. Pepper as a coke (lower case c). Dr. Pepper is always referred to by it's name for some reason. lol
- They may well have been concerned about the Hadozee mistake could happen again, but worse. While it's true that you can't put the label "D&D" on OGL 1.0a licensed material, many people would not care. For them it's used to play D&D, it's labeled "5E", it's sold next to and as a supplement to D&D, it is D&D. The brand can be harmed by other companies because they are associated with D&D.
With or without the OGL, people who aren't familiar with the specific product will confuse it with the more well-known brand. It happens all the time.