Ahh, the old 'unless it's specifically and explicitly denied, regardless of moral or ethical considerations, let alone acting contra to the spirit of the law, then it's okay' defence.
Your misdirection is correct - Jeff Bezos is not responsible for UK legislation - however how Jeff Bezos instructs his vendors and employees to act is very much his responsibility.
If you want to change the tax laws then you can do so, via the government that you take part in.
Amazon is so big that they can jurisdiction shop or even just shop for legislators/civil servants to help fashion the regulatory environment they prefer.
Everything you're saying falls under "change and improve your government" if you want to see something different. If they fail to act in the public interest then vote in someone else, or run for office and show them how it's done.
It's not easy, but it's not impossible. And it's far more realistic than posting some comments and wondering why companies don't magically just donate their money away.
Companies are also not citizens, they are abstract structures designed to deliver value to customers and make a profit in doing so. A corporation has no specific loyalty to the government beyond following the laws and paying the dues required for operating. Corporations are also not able to judge what the "ethical" amount to pay is, which is why the government sets those rules on behalf of the people it represents.
You're turning a government issue into a corporate issue because it sounds easy, but ultimately its just treating (or rather complaining about) the symptom rather than enacting any solution. Again, perhaps you should join the government and enact the change you want to see?
Also since you are talking about responsibility and actions, I assume you donate all the spare cash you have that isn't going to taxes. Or is that not ethical in your case?
No. They don't. Companies do.
To a degree, they DO have a fiduciary duty to maximize profit over the long haul; if Amazon didn't take all legal shortcuts it'd be at a competitive disadvantage and a competitor could put it out of business.
Optimizing every aspect of their operation gives Bezos, the person, the opportunity to act following his moral compass (space exploration, philanthropy, etc.)