Legislation being opposed by large corporations is becoming a decent indicator that passing the law will be beneficial for society and we'd all be better off enacting it.

That, as they say, is the purpose of any corporation. Their responsibility is to their shareholders.

No. This is a mischaracterization of both the purpose of corporations and the responsibility corporations have to their shareholders.

The purpose of a corporation is not "profit above all else". Corporations are also supposed to operate in a manner that benefits society. We used to actually strip corporations of their charters when they failed their social responsibility.

The responsibility to shareholders depends a lot on the charter, but in general, it's to run the company in a profitable and sustainable manner. Again, it's not "make the most money possible no matter what". If that were the case, then there would be no corporations engaging in anything but the highest-margin sorts of business. So there'd be no low-margin stuff like toilet paper.

The purpose of incorporation is to encourage business speculation by offering a mechanism to limit personal liability of the owners. That's the only purpose a corporation has and they definitely don't have responsibilities themselves as they are only a legal fiction. The employees of a corporation have responsibilities.