It is in the sense that Onana did not affect the opponent's ability to play the ball as best as he could in that situation, as it had already happened, and no obvious goal-scoring opportunity was denied either.
Taken from the FA's website, the following factors were surely also taken into consideration and were in favour of Onana here:
- distance between the offence and the goal
- general direction of the play
- likelihood of keeping or gaining control of the ball
- location and number of defenders
No penalty for me.