I can see this. Apples to oranges is a bit extreme. I'll give you Granny Smith vs McIntosh or Macoun because Red Delicious are terrible and DL and MK are both great haha. If you've tried a Granny Smith, you most certainly have not tried a McIntosh.
That said, my point stands that there is enough different about DL and MK that you can't have tried one and claim to have experienced the other or not need to. I can point out as many different aspects between the two parks as I can similarities - maybe twice as many - be it rides, lands, layouts, restaurants and food offerings, shows, stores, etc. I mean, I've been going to Magic Kingdom my entire life and still got turned around a few times trying to locate stuff my first time at Disneyland; the castle being so small and not visible from everywhere in the park is part of that but the paths and lands are really very different.
And that's just discussing the layouts for these two "hub and spoke" parks. After two full days in Disneyland, there is still more I want to see and haven't gotten to explore or experience yet, which is great!