I think things are being said by people who don't really understand the situation. I am one of those people but I did read that the current flow is to the exit. This was an added difficulty for the divers going in, but should assist the kids coming out. There are plenty of other issues but I don't think current is one of them.
I suspect (IANACD) that current from behind would be more of a nuisance than from in front, tending to push your body past your hands, and hands off any handholds. You could go backwards, but then you can't see where you're going.
Sounds like they can't see much due to turbidity anyway - and bright lights, like driving in fog, can make it worse due to the back-scatter).
But yeah, getting pushed along when unsure what's in front would be horrible.