Foot basically exemplifies what @Banno was moving towards in the previous thread: a form of moral relativism that is ultimately based on the conventions of a given society. For Foot morality has the same quality as cultural etiquette, and therefore a moral claim will only be compelling to an individual who is situated within the required cultural milieu:
What we actually have are rules of conduct adopted by certain societies, and individuals within these societies; and Kant is saying that these rules are universally valid.
[…]
But someone who thinks that significant concessions have now been made to Kant must answer the following question. Has anything been said about the inescapability of morality which could not also be said about the inescapability of etiquette?
(Philippa Foot, Virtues and Vices, 171)
Or:
It is obvious that the normative character of moral judgement does not guarantee its reason‐giving force. Moral judgements are normative, but so are judgements of manners, statements of club rules, and many others. Why should the first provide reasons for acting as the others do not? In every case it is because there is a background of teaching that the non‐hypothetical ‘should’ can be used. The behaviour is required, not simply recommended, but the question remains as to why we should do what we are required to do. It is true that moral rules are often enforced much more strictly than the rules of etiquette, and our reluctance to press the non‐hypothetical ‘should’ of etiquette may be one reason why we think of the rules of etiquette as hypothetical imperatives. But are we then to say that there is nothing behind the idea that moral judgements are categorical imperatives but the relative stringency of our moral teaching? I believe that this may have more to do with the matter than the defenders of the categorical imperative would like to admit. For if we look at the kind of thing that is said in its defence we may find ourselves puzzled about what the words can even mean unless we connect them with the feelings that this stringent teaching implants. People talk, for instance, about the ‘binding force’ of morality, but it is not clear what this means if not that we feel ourselves unable to escape. Indeed the ‘inescapability’ of moral requirements is often cited when they are being contrasted with hypothetical imperatives. No one, it is said, escapes the requirements of ethics by having or not having particular interests or desires. Taken in one way this only reiterates the contrast between the ‘should’ of morality and the hypothetical ‘should’, and once more places morality alongside of etiquette. Both are inescapable in that behaviour does not cease to offend against either morality or etiquette because the agent is indifferent to their purposes and to the disapproval he will incur by outing them.
(Philippa Foot, Virtues and Vices, 162)
Or finally:
The conclusion we should draw is that moral judgements have no better claim to be categorical imperatives than do statements about matters of etiquette. People may indeed follow either morality or etiquette without asking why they should do so, but equally well they may not. They may ask for reasons and may reasonably refuse to follow either if reasons are not to be found.
(Philippa Foot, Virtues and Vices, 164)