In my opinion, the biggest thing this assassination did was clarify economic class. Look who came out in strong defense of the CEO, and look who came out in celebration. People used to the simple cultural “left”/“right” lens struggled to make much sense of it, saying this ‘united the country’, but the class divide was bright as day with the owning class panicking together and their politicians and mass media megaphones repeating a pretty consistent chant.
edit: Like you said, what made this noteworthy is the reaction. It reminded me of the antifascist punching Richard Spenser, prompting dozens of news articles asking ‘Is it ok to punch a Nazi?’. Despite being a killing rather than mere physical assault, the audience was far more happy to yell ‘yes’ this time. Economic class is a huge point of unity, growing each day as wealth keeps consolidating, to the point even the suspect from a rich family isn’t immune.
I don’t really disagree with what you’re saying, particularly regarding the response from politicians and assorted media commentators. I think the wider public response is more nuanced than just economic class, however. I believe the response has come more from the victim’s specific industry than just “kill the rich guy”. Similarly, I seriously doubt the reaction would have been remotely the same if the victim was a Millionaire who happened to own a business that made wardrobes. There is a real dissatisfaction with healthcare in the USA and particularly with Health Insurance companies.
The ‘that could have been me’ response was more because many people could see themselves being mad enough at a Health Insurer to kill a CEO than killing some guy because he’s rich. You could of course argue that they are dissatisfied with health care because the care they receive is tied to economic class, and you’d be right. So economic class plays into this response. It isn’t the whole picture, though.