Playing video games for a Let's Play is more difficult than just playing them for fun or challenge. When you're just playing the game, your focus can be on it. When you're doing a Let's Play, you've got to focus on the game, entertaining the audience, and if you're doing the Let's Play with someone else, whatever conversation you're having with your partner in gaming.
This is all very important to acknowledge, as it's even more understandable than it would normally be when they miss something, especially if they've never played the game before or it's been a while since they've played.
All that said and known full well, seeing a Let's Player stuck when I know exactly what to do will sometimes make me desperately say whatever needs to be done to whatever screen I happen to be looking at in spite of the futility of it. I'm not judging their playing when I do (well, not usually), but I have emotions, darn it. I FEEL WITH FEELINGS