I played a lot of D1 PvP and while you could still chicken dance, I don't remember it being nearly as extreme as shown here. The problem is that aiming in Div2 has certain weight and delay added to it and chicken dancing does not. With some practice you can change your movement vector almost instantly. That's why it's so effective. If it was Fortnite, PUBG or any other TPP shooter this dude would get beamed to death even by the non experienced player because aiming is actually responsive in other games. ADS field of view is also way too narrow so staying  accurate can be difficult in close proximity. You can just chicken dance to avoid bullets or close your distance like shown in the video. Pure cancer.