That's just so much meaningless gibberish with misleading conclusions.
Specifically, all corporate taxes paid come from three categories of individuals: consumers, who pay higher prices for items to cover the taxes; employees, who make lower wages to cover the taxes; and shareholders, who earn lower returns (and note that the two former categories are often also shareholders, via their pension plans). Suppliers can also lose, but they're generally corporations as well, with their own employees and investors who actually eat the loss.
Corporate taxes come from one category of individual: those involved with a corporation. This means shareholders. Employees might pay a portion of it, but only if they won't be hired by non-corporations. Consumers might pay a portion of it, but only if there is no competition from non-corporations.
In the long run, though, the investors don't lose because capital flows away from lower returns and towards higher ones. So companies must find ways to keep their returns up to somewhere near the mean rate of return.
A corporate tax lowers the mean rate of return for corporations. Investors could switch to non-corporate investments, but they already have money invested in corporations.
Once you understand that no taxes are paid by corporations, ever, then you should also recognize that corporate taxes are not only ultimately paid by individuals, but the individuals almost never realize they're paying it.
Why not go a little further? No taxes are ever paid by individuals, taxes are paid by protein and DNA molecules. And the protein and DNA molecules almost never realize they're paying it.
How many people know their prices would be lower, wages higher, or pension more secure, if it weren't for corporate taxes?
Very few people, because it takes a special brand of ignorance to think that way. If a lower proportion of the taxes were paid by people involved in corporations, then the tax rate on people not involved in corporations would be higher. Most of us aren't major shareholders...
And, therefore, how many voters have any interest in opposing corporate taxation? To politicians and voters, corporate taxes look almost like free money. Ratchet up the corporate taxes and no people get hurt, just those nasty corporations.
Corporate taxes are the penalty portion of the system designed to allow profits with little or no responsibility. That low responsibility comes with a price. If some investors choose to switch to a form of investment in which they are more responsible due to higher tax burden on corporations, that is fine with me.