If you’re referring to citizens united then that does not grant full personhood to corporations. It just protects free speech from corporations because it views the speech as coming from the individual persons that form up the corporation. This is a very narrow application of rights applied to corporations.

But in general corporations are not granted personhood.

Do we? Not where I live. Corporations cannot vote, etc. The US is an outlier in granting more rights to corporations than other countries.

That's the key issue here. AI forces a re-examination of corporate personhood and corporate responsibility.

Much of conservative US business theory is based on Milton Friedman's famous op-ed in the New York Times in 1970, "The Social Responsibility of Business Is to Increase Its Profits". [1] Go read the original, please. It's short. Friedman ends with "There is one and only one social responsibility of business — to use its resources and engage in activities designed to increase its profits so long as it stays within the rules of the game, which is to say, engages in open and free competition without deception or fraud.”

Anyone arguing against legal personhood for AIs needs to justify holding AIs to a higher standard than that. Or, conversely, allowing corporations to hold to such a low standard.

[1] https://www.nytimes.com/1970/09/13/archives/a-friedman-doctr...

If a corporation does something blatantly illegal like hiring people to deal crack and kill other dealers, its executives will be jailed. If an autonomous robot decided to take up crack dealing, it could back up its brain to a hidden server somewhere so that even if the police caught it and destroyed it, it'd just find another body and continue dealin'. I.e. there's no incentive to behave for a being that's essentially immortal due to being able to make infinite copies of its brain.