If the PF states 'must have seen video' then don't join if you haven't. You should only join a PF if you meet the requirements or message the PF starter if you don't to work it out. It doesn't matter if you agree with it or not.
That being said, when I create a learning party or join one, I'll always give a short run down of the fight that starts with "Don't die, avoid death and don't get killed."
For the more complex patterns where a lot more is happening, yeah it might be easier to have seen a video. Doesn't necessarily mean people will understand it.
A clear and concise (which is what most videos lack) short run down of what to look out for, plus giving it one go just to experience the fight will help me more than watching a video. It's just how you process info in your noggin'.
I hear and I forget. I see and I remember. I do and I understand. Confucius