I saw this video on YouTube

I was just wondering why is it that the front and rear tires tread pattern are flipped?

Because the front and rear tyres peform different functions. The rear tyre is designed to provide traction under acceleration and has a minimal effect when braking or even cornering compared to the front. Since you want the rear tyre to grip and push the bike, you want the front to provide as little resistance as possible. Likewise, when you're attempting a turn, the 'reversed' pattern of the front tyre 'opens up' a bit and provides the added traction that allows the bike to corner...or brake. The manufcaturers know this and when the make their tyres even lay the base layers down so that accelerating causes the rear tyre to compress the ends together and braking causes the front to compress its base layers ends together.

Metzler even instructs you to reverse the arrow if using a rear tyre on the front.

Not having owned a scooter before living in Thailand I was not aware of that.

Thanks a lot Dave for your comment, it really makes sense to me know.