Nonetheless, it's the lack of charity that I've encountered on the part of some Traditionalists that sticks with me. Notwithstanding the question of whether the NO Mass is valid*, one can be 100% theologically correct and 100% condemned out of a lack of charity. St. Paul says in 1 Corinthians
1 If I speak with the tongues of men, and of angels, and have not charity, I am become as sounding brass, or a tinkling cymbal. 2 And if I should have prophecy and should know all mysteries, and all knowledge, and if I should have all faith, so that I could remove mountains, and have not charity, I am nothing. 3 And if I should distribute all my goods to feed the poor, and if I should deliver my body to be burned, and have not charity, it profiteth me nothing.
Peter also speaks on the importance of charity (1 Peter 8): "But before all things have a constant mutual charity among yourselves: for charity covereth a multitude of sins."
Does this mean that charity excuses syncretism or indifferentism? No. However, one can be inculpably ignorant of matters of the faith (such as the requirement for the sacrament of reconciliation). I don't see how one can be knowledgeable of matters of faith but inculpably ignorant concerning the requirement for charity.
*I think it is a matter of faith that the Novus Ordo is a valid rite, if only in the sense that the Pope has the right to promulgate changes in the manner of worship (that is, in liturgical norms or discipline). Whether or not the Novus Ordo (when celebrated correctly) is as reverent as the Tridentine rite, in my opinion, is a matter of subjective judgment (as well as a matter of personal practice). However, unless I'm willing to claim that Pope Paul VI was not a legitimate Pope (and I'm NOT willing to accept that), I have to accept that he had the right to make decisions concerning the practice of worship, and that we are obligated to accept them as valid (not necessarily good). Where Rome is, there is the Church, or, as St. Augustine said, "Rome has spoken; the case is closed."
UPDATE: I read this interview with Dr. Alice von Hildebrand on Phillip Blosser's blog that discusses the TLM and problems with irreverence. I do think there's some legitimacy to the idea that it's more difficult for liturgical abuses to creep in when the liturgical language is not a native, living language. Not many priests would be so fluent in Latin that they could perform the liturgy off the cuff. However, Dr. von Hildebrand's point is that the irreverence was present prior to the change to the NO. Reverence is foremost an interior response. It can be reflected in various external forms.