I've no problem with that summary. I don't believe in the idea that morality is the way to get people to pay more than the law requires. I gather David Cameron believes that.

Morality is for guiding people as to what they do with what's left over after paying tax.

So far as tax is concerned, the way to deal with it is to set the rules in such a way that people can't avoid paying tax by clever ploys. Call them "loopholes" or "legal minimising schemes", either way, the thing is that, if we can block them and raise more tax, that's in everyone's interests. Including the people who take advantage of them. A somewhat more equal society is better for everyone.