What, precisely, is "sentimentalized kitsch"? The answer to that question should be a definition, not an example.
Kitsch is a German word that isn't readily translatable. It's the antonym of "kunst", which is not just "art" as we understand the word, but "art" with all its overtones of merit and accomplishment and skill. Kitsch applies to a product that's shoddy or bogus or feeble because the goal lies beyond the artist's technical, aesthetic, or philosophical range. It's an artistic (not necessarily aesthetic) miscarriage, especially one that fails through the incompetence, ignorance, or negligence of the artist.
The Coca-Cola Santa is kitsch. Treacly religious art is kitsch. Even though they may be well-drawn, because they're manipulative and sentimental -- or rather, manipulative because they're sentimental. They exist to comfort us with the message that everything's OK. They conform themselves to our expectations. They're kitsch not because the artist lacks technical skill, but because the skill is debauched in the service of something less than truth.
I might add that the Novus Ordo Mass as all-too-often celebrated in AmChurch environs is, notwithstanding its validity, kitsch, by virtue of dishonest translation and insipid language, shabby vestments, lack of due regard for liturgical reverence, and relentlessly commonplace, utilitarian setting, decorations, altar vessels, etc.
The excessive realism of later religious art, especially in the West, is spiritually dangerous not just because it's sentimental, but also because it supresses the vertical dimension, the element of mystery.
With reference to the spiritual danger of sentimentality in art, please consider what Walker Percy or (even more) Flannery O'Connor had to say. O'Connor points out that sentimentality is tenderness detached from the source of tenderness. It is tenderness for its own sake, thus it makes the individualised self the standard of truth and beauty, rather than anything eternal. Because sentimentality recoils from what's not emotionally congenial, it devolves into self-worship. And once self-worship sets in, any cruelty imaginable can result. As O'Connor concludes" "When tenderness is detached from the source of tenderness [i.e., Christ] its logical outcome is terror. It ends in forced-labor camps and in the fumes of the gas chamber."