He's Massa Mk2, hasn't learned anything since being in F1. Massa still turns in on anyone at all when he believes a corner is his(which happens if these conditions are met... 1 he's in a corner and 2 his name is Massa) and after over a decade in the sport he still instantly blames the other guy while also usually accusing them of being young and not having learned yet.
Vettel and Kimi have been in numerous incidents in the past few years where they make dangerous assumptions that lead to collisions and I feel this was another one. Vettel can see him the whole way yet never even reacts, Stroll sees him for a tiny fraction of a second before he reacts. One of the issues is the FIA, and Ferrari, or is that the same issue. Massa spent years with Ferrari smashing into everyone, ruining race after race but screaming at others and importantly never being punished for it. If he was punished he might learn what he was doing was wrong. If Vettel was punished for anything he did wrong... he might learn not to do it, but when he gets away with every bad piece of driving he does and gets to blame the other guy with the FIA backing him up (by not punishing him when he is clearly at fault) he's taught that he's right, to be wrong would mean being punished for it.
