Answer:
A sanctimonious posture is always, by definition, unmerited.
The adjective sanctimonious describes a person who behaves in a pious, righteous way, a person who believes, or pretends to believe, and seeks to convince others, that they are better than others when it comes to ethical behaviour, religious beliefs, and so on.
Just as truly honest people feel no need to go around telling everyone how honest they are, and truly kind people don't make a big deal of their kindness, so truly ethical, highly-principled people don't tell the world that this is what they are. They simply show it by their actions.
Those who tell the world how good they are are doing so for some personal gain; whether it's financial, or to have people respect them or like them, or for some other gain, they are bragging about their personal sanctity because they want something.
A person who lives a life of true sanctity doesn't brag about it; true goodness demonstrates itself: a virtuous person shows their goodness with every word and action.
When you meet someone who is anxious to tell you how good they are, in any sense, watch out.