I think he did try to deviate.
As he approaches the child, the child is looking right at him so I think he expected the child to move. As he got closer and and it became apparent this wasn't going to happen, he tries to move one way, then the other - each time this is matched by the child doing the same. They are micro gestures on both sides.
They then essentially run our of time and collide, the child falls to the ground and the guard lifts his leg up high to prevent kicking him/step over him.
I think eloquent arguments could be made on either side of this, tbh and if it's true the guard immediately went back to check the child was ok, that would lend a different view again.
But the hypobol and emotive language used in some previous posts is weaking that argument (on both sides). Bringing in Tiananmen Square footage is frankly the pinnacle of this.
The parents are neither fuckwits, nor the child stupid but nor is the guard brutal and he doesn't kick or trample anyone.
'Two people collide' is not a massive deal. The guard could have stopped, the child could have stood out the way as instructed at the start. Neither did and, ultimately, little harm was done.