Scripture to support that, please? And where does it say that a person must be sinless to house God? You have acknowledged that God - in the form of His Holy Spirit - resides in all of us, and we're not sinless. God clearly can reside in a failed, sinful man. Mary does NOT have to be sinless to be the mother of Christ.
How many times have I said that now?
You have said it many times, but have not given any scriptural basis for the sinless nature of Mary. You have made the claim and stated that it is by your logical conclusion only (and that of the Catechism).
Likewise with the original article that started this thread - it appeals to tradition only, without a scriptural basis for the claim made.
In fact, I would even posit that it's appeal to tradition is incorrect as this position - Mary's infallible nature - is only from 1854, and does not reflect the traditions of the Orthodox Church which is as old and steeped in tradition as the Catholic Church!
You believe Mary was sinless; I do not. This is a case where the scriptures do not support the Catholic position, but in fact provides evidence to the contrary. Witness Stephen being full of grace; the perfect counterpoint to the demands that a person must be sinless to be full of grace and filled with God in the form of His Holy Spirit.
We already went through this.
Luke 1 -- "Hail, Mary, full of grace."