Just a small correction: here's what the solemn declaration of the Immaculate Conception by Blessed Pius IX said: "We declare, pronounce, and define that the doctrine which holds that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin, is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful."
“is a doctrine revealed by God and therefore to be believed firmly and constantly by all the faithful.”
Yes, I believe the teaching is inspired. I believe that anyone who has sufficient time to investigate the question will come to the same conclusion.
However, that time and ability is not available to everyone. Salvation is left to God to read our hearts and minds.
Mary wasn’t born without sin. The Bible says we are all born in sin, “all have fallen short.”
If God could have chosen one born and made them sinless He wouldn’t have needed Jesus’ sacrifice, He could have made us all sinless if He made Mary sinless.
And if you say Mary had to be born sinless (which the Bible says is not true for anyone except Jesus) because she carried Jesus, then why wouldn’t God have made Anne also sinless, as she carried a sinless Mary?
And on and on...