It doesn't, that's not what I'm saying. I'm saying that VAR found a reason to disallow the goal that was utter bullshit and isn't actually consistent with their own rules.
They've just put the offside rules up, every line of the rules stares "which impacts the ability of the opponent to play the ball", nothing Armstrong did prevented anyone from playing the ball.
You can because he flagged for offside against Archer which is why they checked that first. Then they looked for any other reason to disallow it once they realised Archer was onside.
Not very professional from McCarthy there to not be warming up. If he genuinely is injured then having him on the bench instead of a youth keeper is ridiculous.