In my experience, help line people don't tend to be the best and brightest but delight in misunderstanding the customer and would rather have a cheap laugh at their expense than bother to actually help them.
Draw a triangle on a piece of paper and ask 100 people what it is and most will say a triangle, not an arrow. The fact that people are phoning up for help points at the fact that they are not technically competent so telling them to look for an arrow instead of a triangle isnt going to help. The fact they are confused and looking at 50 odd buttons coupled with their worry about pressing the wrong button and im sure they love talking to some muppet at a support centre who can't give clear, concise instructions over the phone.
Everything is simple when you know how its done. There is a talent to helping others learn and to make them feel stupid because you can't give good instruction is a bit sad really.
That's in a completely different context though. Of course it would appear as just a triangle drawn on a piece of paper, but when it's on a remote control it's completely different. It's like saying "I drew a red circle on a piece of paper and asked 100 people what they thought it was and most of them said the laser dot from a sniper! No one said the red button from my TV control though, which is what I meant it to be!" That's the same kinda logic you're using there.
It's nothing to do with being technologically competent because these "arrows" aren't technological at all. It's simply pointing in different directions, and they are used a lot in every day life to mean directional arrows. Just look at the play button on a remote control, it's a triangle pointing to the right, I'd assume that would mean "forward arrow" considering the fast forward button is two right pointing triangles, and the rewind button is two left facing triangle.
It should be safe to assume a lot of people would get this, but obviously in the OP's case it's not.