The still image doesn't really tell the whole story. Onana takes the touch because the first time pass just isn't on because of the angle and the pitch. If he scuffs it, you'd have people in here saying he should have booted it or taken a touch. For me De Ligt then has to step towards him, it's a simple ten yard pass then and then he can pop it off out to the right.
The biggest part to be critical of Onana for me is that he should drop out more towards the side when Martinez is playing the pass to him, he'd give him a better angle and then he'd have more options on where to go with it when he does take the touch. When that ball came to him, he couldn't go right because he'd be closed down right in the centre of his goal, he can't go back to Martinez, because he's not given himself a good angle to play it back that way. He's then got 2 options, ping it long or play De Ligt. They're being told to play out, so that's what is going to happen, he wants De Ligt to step in there and he doesn't do it. If he steps then it doesn't happen.
It's very easy to lay all the blame on Onana for the pass, but De Ligt has to go towards him and actually show that he wants the ball, he didn't.
The BBC have a whole article on it today.
https://www.bbc.com/sport/football/articles/cy4pvwgv88qo