Roman Catholics are a sentimental lot; and the more traditionally-minded, the more sentimental. How can we not be sentimental, when we see our faith in terms of family -- our Father in heaven, our Mother Mary, our Mother the Church, our brother Jesus, our brothers and sisters in Christ -- where those family relationships are not metaphorical, but literal and incarnate? And just look at the religious devotions of the past few centuries; not just the Rosary -- in which we pray to Mamma Mary as we meditate on Baby Jesus and Suffering Jesus -- but the Sacred Heart of Jesus (which was a big deal not so long ago) and the Immaculate Heart of Mary (ditto)).
So I suppose it's not too surprising that Roman Catholics are susceptible to committing what I'll call the logical fallacy of sentimentalism -- an invalid appeal to strongly-held emotions. This tendency is a problem not only because the fallacy (since it's invalid) can cause someone to assert a falsehood. Even when it's used to argue for the truth, it can backfire and cause people to resist the truth more than they had before hearing the sentimentalist argument.
For the record, we can distinguish between sentimentalism as a habit -- i.e., habitually feeling strong emotions about things -- and sentimentalism as a fallacy -- i.e., arguing that strongly felt emotions prove something that they don't in fact prove. We could even call the former "sentimentality," and say there's nothing wrong with it as such, though as with all emotions, those held strongly are to be ruled by right reason.