Edward Abbey said, "Sentiment without action is the ruin of the soul." This quote could lead in a hundred ways, but suffice to say, it opens the door to investigating the deleterious results of sentiment.
Sentimental objects in our life, fires we huddle around. Objects that give us meaning, and purpose, and identity. All good things at first glance, but at second glance?
They can become objects of tyranny. Think of the tenured professor. Who does the tenured professor pay sentiment to? Their position and the system that has esteemed them. A school teacher with benefits and job security. The system that you have power within is to be revered.
Religious are perhaps some of the most sentimental. A minister in a cushy cleric position. Naturally, the minister is sentimental to where their power and well-being derives. Religious adherents are often just as taken in, especially in religious systems that offer absolute truth; salvation through special knowledge and experience; and a dominating sense of exceptionalism. This kind of sentimentality appeals. It is warm and cozy to know that your in-group is exceptional and exceedingly special the world over. It is more than appealing, it is intoxicating.
Ironic that the great teachers of truth were something less than sentimental preservers of tradition. They are unique not because they started something popular and appealing that would lead to even more versions of sentimentality. They critiqued the revered way, the sentimental way, when it became set in its ways and forgetful of the way of truth.
A poem by Ryokan as antidote: The thief left it behind/The moon at my window.