What is this minion block

Agreed, minion block is a huge and irritating problem.

EDIT: Your video doesn't work. It's a private link.

I could understand enemy minions blocking people, like a hostile unit collision, but it doesn't work that way. It feels like those CoD videos you see with allies trapping each other in corners. But there are flaws to not giving unit collision to allied units as well.

Without unit collision applying to everybody you could stack a growing champ like Zac or Cho'Gath (even a big champ like sion) over top a whole team and keep them from being able to hit anybody under them. A basic champion could deny CS by standing over top of a minion as well. It's not entirely black and white, but let's see what happens.

I've never experienced so much minion block as when I started playing Xayah. No idea why, but I lose kills on her on almost every game because she can't fit through the wave. I'm fine with enemy minion block but when your own casters create a barricade across half the lane it's ridiculous.

I can't even tell you how many times my own minions have gotten me killed.