Heavier unrequited stuff aside, I kinda hate riddles like the one we just saw. They basically just boil down to "guess which way the creator wants you to interpret the riddle" instead of having an actually intuitive answer.
I love how you just skipped all talk about the heavier unrequited stuff to comment this and yes, somebody had to say that!
At first I thought the point was to confuse you into thinking that the elephants were also going to the river. Then I realised that the catch was actually "all elephants saw the same two monkeys", but. Where is that specified in the narration? From what I read it could just as well have been that each elephant was moving separately and came across a different pair of monkeys, or even that some of the elephants saw the same monkeys and others saw different. There is nothing in this riddle that would make either answer more correct. In fact, perhaps the only "correct" answer would be to point out the incompleteness of the riddle itself.