Why do you consider it so strongly to be inappropriate? It literally does not tell me anything about the user.
DOS was built in a basement. Pretty sure suit and tie wasn't the dejour whilst they were doing it.
Linux was a hobby project. Pretty sure that slacks featured more than a blazer.
I will tell on myself here but having an anime pfp evokes something childish for me and I do judge the user based on it. I expect to be judged similarly because I use the album art for a favorite album of mine as a pfp on the same platform and would consider it equally inappropriate if I were to share a heartfelt and serious message like this one.
That sounds like you associate anime with childhood cartoons? But considering how much of that industry output is 16+ or 18+ (usually violence and themes), I'd say that is more of a cultural confabulation.
I would absolutely not expect a business profile image, regardless of the message. Nor do I get why you think it is so essential.
Half the red team industry are furries. Would you criticise them for not using a mugshot? Because a lot of them don't, whilst posting CVEs that affect half the world.
https://news.ycombinator.com/item?id=36091595