Why so dismissive? Maybe he does have mental health problems or went off the deep end of anti-vax conspiracies, but you wouldn't do something so drastic if there wasn't a huge amount of suffering there, or the perception of worse to come. All we have for the moment are the eyewitness reports:
‘He was screaming about mandates. He was screaming: no vax ID and throwing books. [...] He was off his face screaming about the mandates,’
ie: not just 'because of an injection', but the way it has been imposed and the social (or personal) ramifications of that.