What I take offence at is the assumption, as exemplified by Keith A of Hartford, that the majority of British people are blithely in favour of the monarchy.

It is not an assumption.
Numerous surveys beside the Guardian one I quoted have confirmed that fact.

small wonder, given the tumult of sycophantic reporting that rains (reigns?) down on us via the Mail, the Express and all the other bits of biased media.

Do you really believe that but for the media everyone would think like you?
Are you somehow immune to it, but lesser mortals are helpless?
The fact is that only a small minority of people read any newspapers at all.
Face it. Most people just do not like, want or believe the stuff that all you do.