Kimi already punched him in the face, err, no, into the wall, I mean
For me Kimi just had enough with his moves and wanted to show Checo that it's not only him who can make bold moves.
Got to love Kimi for not being like Alonso - "Hmm I'm a championship contender and hence I should be saving maximum points, let's just let him past. He'll end up breaking something anyway".
Instead he went "I'm not going to just give it to you, motherfxxxer." =D> =D>
As to penalty? As stated above I think the "alongside" argument is moot so one cannot say Kimi "had to" leave a space. However I do think the gap existed, and Checo went for it. So for me both drivers did what they were entitled to do and it was a racing incident.
Oh another thing. There was in fact a little bit of wheel-locking and smoke from Checo - but then that was when he realized Kimi wasn't yielding and he might be braking extra-hard and locked-up, so I don't see clear evidence Checo was "outbreaking himself" or "wouldn't have made the corner anyway".