Genetics certainly don't explain all the differences in IQ. They very well might not explain the majority of the the difference. However, considering we know that intelligence is quite heritable along with various adoption and twin studies that have happened throughout the decades (along with simple freaking logic), we have a pretty good idea that it explains at least some of the difference. That "opinion poll," while not super-great because only some elected to reply, was a poll of experts in the fields that study this stuff, not random people.
A real unbiased article would mention that (and perhaps whatever counterarguments there are), not straight up do the encyclopedia equivalent of sticking their fingers in their ears and going "nah uh I can't hear you."
Bringing up an opinion poll as a counterpoint makes it read like you're arguing that Wikipedia should focus less on fact and more on opinion. Of course, you're free to think what you wish, but I suspect that's where most disagree.