Well said. It is clear that if Calvin’s kids suffered the same doubts as Mother Teresa, they would not persevere, they’d just drop it and walk away from the call of Christ.
Frankly, I shudder to think why anyone would denigrate Mother Teresa’s example. Perhaps they are trying to discourage other Catholics from persisting in service to God. If so, and if they are successful, then God will not hold them blameless.
St. John OTC, after coming through his darkness (if you read the story of his life, and what was done to him “darkness” is too poor a term.), he said that what he realized looking back is that when he felt the most alone was the time when God was closest.