I agree with you overall, it was definitely a very "raw" and vulnerable post.
I wasn't one of the downvoters, but I think those "couple interesting tidbits" might be the reason for downvotes. People aren't comfortable reading someone's delusions of grandeur, even if they might be true. It is just off-putting to hear someone very confidently proclaim "under the hood I am a genius and a mess" and "my ideas, creativity, research and insights result in massive wins. But other people always get the credit". The post can easily be interpreted as a "oh woe poor me, I am a super productive genius who turns everything he touches into gold, but people like me never win the corporate game because the system is rigged" type of a humblebrag that is not being entirely truthful.
Again, even if it is actually the truth, it just leaves a sour taste. Probably because all of it seems like just shifting the blame onto everyone else and going on a rant that can be boiled down to "I am a misunderstood genius, but everyone else gets the credit every single time for every massive win I get for my company, because great winners like me just never get to win in corporate, the system is rigged".
This is quite out there and is something a lot of people with some heavy overestimation of their abilities say. Because to them it seems like they are "losing the corporate game" due to them somehow being discriminated against for their ingenuity and smarts, and not due to their actual lack of ability coupled with massive overconfidence in their ability. After all, as the famous quote says, if everywhere you go you see assholes, you might be the one who is the asshole.