But I'm not sure the logic is even worth following: "calling" for a republic is
1) It's a commonplace observation that we, unlike a number of our European friends, missed the 18th century - or at the latest, 19th century - window where monarchs were dethroned, sensationally in France beheaded, and replaced with a republican constitution. There have, of course, been 20th century examples too - but these have followed either independence, defeat in war or some other form of regime-change. This has not been Britain's experience.
2) To this we should add the observation that we have had a republic - before the French and before the Americans - under this miserable sod. Difficult one this. You're in the Unbearable Lightness of Being territory if you insist his reign bequeathed Britain lots of constitutional goodness. The historian in me would agree - but those living in rather closer historical proximity to the tyranny of this appalling Calvinist bigot didn't feel the need to repeat the republican experience - and for good reason, in my view. The point is, this had obvious knock-on effects for subsequent generations.
3) 'Republican' in the minds of many people of a certain age - and not just those of limited education - is synonymous with Irish terrorism. There were, and are, those of the left-loathing left who equated this with 'freedom fighting' - but I think it would be fair to suggest that these were always in the minority - leaving republicanism as a concept, undoubtedly unfairly, stained with blood in the minds of many.
Add to this the observation that democracies that are also constitutional monarchies have been the most stable - a point repeated most recently by Eric Hobsbawm here - leaves me wondering what is left of my republican views? An idea on paper that has no prospect of happening and may not even be desirable if it happened. A fairly pointless view then - so it is certainly a waste of time bringing it up in Parliament, I would have thought - especially if you're only going to allude to it - which is what Evan Davis was doing.