Bismillahir Rahmanir Raheem,
As-Salaamu 'Alaykum Wa Rahmatullah
This is not as wierd as it seems. It's totally wrong. But if you wonder why they do it, not all, but a lot appears to be too much excitement. Due to not having a structered outlet the way the Muslims do, they end up doing this.
This is why it is so important to stick to Islamic ordained acts of worship.
The outbursts you find are not something amazing, I mean, kids sometimes get so excited they don't know what to do, and just run around.
Us adults sometimes use the common phrase "I just want to scream and shout" etc. when we find out good news, you see some people when they win money or something jump around and so on.
Some of the people in the video feel such a satisfaction from what they think is a reletionship from God they get extremely excited, and whereas a Muslim following the Sunnah would retain composure and do what is found in the Sunnah, these people do what comes naturally, i.e. jumping, screaming, etc.
Although some other Churches discourage this.
Some of it, I think, is plain shayatin either fake people or jinn.
And Allah knows best about that.
One lessons to take whenever you see this: Stick to the Sunnah in your worship.
Br.al-Habeshi
