I didn't know that, and its interesting, but I'm not sure it necessarily changes things. He still did, whatever his feelings, lead the army and in the 1820s and 1830s that would have been the story. He might well have had misgivings about what Fernando did afterwards, but how does he demonstrate that to the public at the time? Remember this is a time of fervid rumour and wild conspiracy - large numbers of Frenchmen and women were convinced, for example, that Bonaparte was secretly still alive in the 1820s and might return to liberate them once more.
Whatever he does, Louis XIX will be dogged with the reputation of having suppressed a Liberal regime with force and this will affect how people treat him politically if he lasts as king.