Now, there's a human being without sin? Mary is without sin? That's contradicting the christian teachings of the original sin.....isn't it?
Is there a (logical) explanation?
It is a contradiction Omya, and no there is no logical explanation for it, from a Christian perspective, which is why I and others have said that for the true Christian it is not possible to accept it, and no where in Scriptures is it ever even suggested.
Yes, there are some in the group of religious people called Catholics who do follow that teaching, they do have their reasons, some of which are mentioned here in the listed quotes, including your own.
True Christians can't agree to it though as it is not a Biblically based doctrine The bible teaches very definitely that "All have sinned and fallen short of the glory of God". (except of course for Jesus, who the Bible teaches in 2 Corinthians 5:21 was the only one ever born who was without sin "God made Him who had no sin, to be made sin for us)
Most of us on this forum as believers would have to agree with you completely on this one Omya.