Of course I understand that in the context of scientific research you can’t just assume, it’s just a bit absurd from the outside.
Would rather drink the water used to clean chicken shit off the deck than anything else
Would die of thirst rather than drink slightly dusty, dog saliva contaminated water from their bowl. That Must Be Clean! Now, human!!
Tell that to my cats. If they got the chance they will always prefer to drink from puddles of muddy rainwater instead of the clean water we give them.
I mean, it could also not be about taste at all, I'm sure not all animals taste things the same, not even all humans have the same taste it seems, I can't stand fish and I love licorice, many are the opposite :)
Besides, many animals seem to enjoy just "different" things. When I'm out and about with my dogs, they love trying to drink water from puddles, even if I have a portable bowl with fresh water right next to it. Maybe it's more "interesting" or "flavorful"? Who knows...