Not true at all. I don't know about you, but I'm always attentive to my opponent's shots from the sideline, in case they foul. As a player, you can't rely on the ethics of another player, so you must watch for fouls. This is why the responsibility should fall on the non-shooting player, because it's in their self interest, and theirs alone.
Obviously, sitting on the sideline, you won't always be able to detect a foul, but anything that is close, you can simply ask the shooting player if it was a foul. If that player then lies, well that would be considered cheating.
The foul in question doesn't require a special vantage point. Both players could clearly see it, and everyone in the room could clearly see it. Anytime it's close, or the non-shooting player doesn't know if it was a legal hit or not, all they have to do is ask. Just as if you scratch, you shouldn't have to alert the other player that a foul occurred, you shouldn't be required to point out fouls, unless there's no way the opponent could know you fouled.
Again, I have no issue with explicitly stating in the rules that you are required to make sure your opponent is aware you fouled, even if it's obvious. But without a specific rule in place, it just doesn't make sense. There was nothing preventing Loree Jon from recognizing a foul occurred and taking ball in hand. It's her fault the foul went unpunished.
I guarantee you that Loree Jon was not upset at Jennifer because she lost the match based on not recognizing a foul occurred. She is blaming herself, as would any player who fails to notice something so obvious that could have won them the match.