I do not doubt that you would laugh. Which, generally, is the wrong way to approach someone trying to explain their views.
Did you not see where I specifically answered the question:
"Player: What about sea elves and other aquatic races?
DM: They do not exist because of the physiological reasons I gave."
Why is trying to adhere to some sense of biological realism the "worst" reason? The single sahuagin god in my example gave them an ability
and they are creatures. Notice the DM also said - they DIE when out of the water. What is that PC going to do when they are out of water? See how there is a logical consistency there.
- DM: Oh, you want to be like the suahagin and be blessed by the shark god. Um... okay, but how will you trek through the desert? The forest? The city? Are the other characters carrying around an aquarium?
As for the other creatures you listed, I would think a good DM could defend those or leave them out. Necromantic magic is a strong and powerful force. Owlbears were the creation of a wizard, much like a liger, only stranger. There are no sentient golems. They are inanimate objects that are able to move through spells and components. Oozes are creatures, just like a worm, only deadly. And dragons, there is a fly spell.
I'd imagine a thorough DM would have a backstory on all of it and reasons why these creatures exist.
And I will leave you with this.
"If a spaceman showed up to help fight Sauron the book would lose all sense of realism for the reader. If a cowboy showed up and killed Ned Stark people would have stopped watching at season one. Of course, that might have been a good thing." -