That's often trotted out. What's not highlighted quite so often was the monarchists role franco to power then their tireless work hand in hand to the open fascists of the falange and franco's far-right authoritarian dictators to sustain and legitimise the rule and to put it in such a dominating position that it would never be effectively challenged again. And that involved playing a role in then covering up then justifying the post-war murders of tens if not thousands of people, then doing the same with the ongoing actions of the police state - the mass jailings, the continuous primitive executions by garroting, the spying on then stamping down on any forms of independent political organisation - all this administered and ran by the nice democratic monarchists (and spain was a kingdom all this time btw - there was no king, but the state was a monarchy) and the plundering of the state and its people.
And this is rarely mentioned precisely because it would undermine the myth of the democratic transition - the one where the old elites retain all their power and any hint of ideological contamination from Portugal or the rebirth of influence of the old left and anarchist groups is sidelined and outcast by our new democrats - the one where the state changes form but the content largely stays the same. The one where the elites fear of challenges to their power was sold as fear of civil war.
There's only one sane response to such democrats.