I can see how they interpreted the law to give it. However, the “interfering with play by playing or touching a ball passed or touched by a team-mate…” bit is key to me. It separates ‘playing’ and ‘touching’ as two different things. A lot of the ‘it’s ok’ argument seems to rest on them being the same.
Rashford charged after the ball and was in any meaningful sense in possession. He was ‘playing’ the ball, as otherwise why did he run where he ran? If he had stopped his run and allowed the other player to come through then I get it.
Otherwise the absurd defensive response to this is fouling Rashford, in which case he becomes active.
I also think he impacts opponents, but that is secondary.