Feast of Immaculate Conception of the Blessed Virgin Mary

Today, the Catholic Church celebrates the Immaculate Conception of the Blessed Virgin Mary. This dogma was pronounced by Pope Pius IX in 1854. Technically speaking, it says
the Blessed Virgin Mary, in the first instance of her conception, by a singular privilege and grace granted by God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved exempted from all stain of original sin (Ineffabilis Deus).
I have to admit beforehand that I am not a theology student. Therefore, my discussion on the topic should not carry any weight. Indeed, this doctrine has been controversial all along until the pronouncement in 1854. This only shows that we are rational and non-complacent. We work very hard to try to understand what we believe in. Before the Pope made such a pronouncement, he had consulted many bishops the majority of whom supported this doctrine. Of course, the majority could be wrong and mob logic cannot be right. I have no intention and am in no position to stir up any more controversy. The following can only serve as a personal reflection on this doctrine.
Purity and chastity are noble values upheld and enshrined by the Catholic Church. That is why Catholic priests and nuns do not marry. They bear witness to these values with their celibate life. The Catholic Church honours many saints who were virgins. The Mother of Christ is held to be a perpetual virgin, even after giving birth to Jesus. All these are the fruits of upholding these purity and chastity values.
When it came to the purity and sinlessness of Mary, Catholics are emotional. They hold dear Jesus' words on the cross, telling Mary to take care of the young Church and the Church to honour Mary as their mother (John 19:26-27). Catholics denied Joseph's sexual obligation towards Mary and vice versa (1 Corinthians 7:3-5). Therefore, they interpret the 'brother of James and Joses and Judas and Simon' (Mark 6:3) to be cousins or children of Joseph from a former marriage. Below their subconsciousness, Catholics hold high the status of priests and make married life a second-class vocation. Luckily, in the 21st century, we see the late Pope John Paul II canonize married women. Married life is no longer second-class.
Why should Mary be sinless from conception and not some time later? Jesus was not yet born. Would it be too risky to grant her such purity and Mary declined to be the Mother of Jesus at Annunciation? Theologians like to quote the principle designed by Anselm of Canterbury "potuit, decuit, ergo fecit" (God could do it, it was appropriate to do, therefore God did it.).
Of course, God could do anything. But was it appropriate? Was it necessary for Mary to be immaculate the very first instance of her conception? Was it possible for Mary to be immaculate some time later, say at Annunciation? Even if Mary were stained by the Original Sin, would it affect Jesus? Could we not simply have the Immaculate Conception of Jesus? If Mary could remain unstained in the womb of Anna for nine months, would it not be more appropriate for Jesus to remain unstained in the womb of Mary? Then, we don't have to postulate an extra privilege to take care of Mary. Of course, God is generous. He could grant favour to whoever pleases Him. Mary certainly found favour in God's sight.
The Catholic Church has to defend certain values. Throughout history, her theological reflections have been very active and fruitful. I am sure the doctrine of Immaculate Conception will continue to generate newer reflection on God's active involvement in our salvation.

Avē Marīa, grātia plēna, Dominus tēcum. Benedicta tū in mulieribus, et benedictus frūctus ventris tuī, Iēsus.Sancta Marīa, Māter Deī, ōrā prō nōbīs peccātōribus, nunc et in hōrā mortis nostræ. Āmēn.