"Your" Virgin

One of the ignorant detractors of Mary, commented about "your" virgin, meaning Catholics, today.  How is Mary our virgin?  Since this protestant says she is a Sola Scripturist, why does she not believe in Scripture?  (Quotes from the NIV, not a Catholic Bible.)

""The Virgin will be with child and will give birth to a son, and they will call him Immanuel"--which means "God with us.""  (Matt 1:23)

Which refers back to:
"Therefore the Lord himself will give you a sign:  The virgin will be with child and will give birth to a son and will call him Immanuel."  (Isa 7:14)

"In the sixth month, God sent the angel Gabriel to Nazareth, a town in Galilee, to a virgin pledged to be married to a man named Joseph, a descendant of David.  The virgin's name was Mary."  (Lk 1:26,27)

"How will this be,"  Mary asked the angel, "since I am a virgin?"  (Lk 1:34)

Those who are members of His Church understand that those outside His Body, and continue to protest her teachings, but still call themselves Christians, have to rebel against all teachings of the Church no matter what.  Mary is not "our" virgin.  She is THE virgin of Scripture.  If you don't believe that you're not a sola scripturist, let alone a Christian.  If you don't believe that Mary was a virgin, then the Holy Spirit was not His Father, and Jesus is not the second person of the Holy Trinity.  Therefore He is not God, and you cannot be a Christian. 

Now, I understand that many protestants do not believe in Mary being "ever-virgin."  Calling her the "Blessed Virgin" is not going to make Catholics think that you accept that Mary stayed in the virginal state all her life.  We understand that.  But to object to a title, such as the "Blessed Virgin Mary," just because you feel you must be anti-Catholic, is just beyond ridiculous.  Mary is the Blessed Virgin of Scripture (I have referred to "virgin" above):

"...Elizabeth was filled with the Holy Spirit.  In a loud voice she exclaimed, "Blessed are you among women, and blessed is the child you will bear!  But why am I so favored that the mother of my Lord should come to me?...Blessed is she who has believed that what the Lord has said to her will be accomplished!"  (Lk 1:41b-45)

"From now on all generations will call me [Mary] blessed, for the Mighty One has done great things for me--holy is His name."  (Lk 1:48)

Actually, the question should be:  If one claims sola scriptura, why don't they call her the Blessed Virgin, too?  That is who Mary is in Scripture.