Actually, you are incorrect.
As noted above, even the 16th century "reformers" themselves confessed "Mariam semper virginem":
"There have been certain folk who have wished to suggest from this passage [Matthew 1:25] that the Virgin Mary had other children than the Son of God, and that Joseph had dwelt with her later; but what folly this is! For the gospel writer did not wish to record what happened afterwards; he simply wished to make clear Joseph's obedience and to show that Joseph had been well and truly assured that it was God who had sent His angel to Mary." John Calvin, Sermon on Matthew 1:22-25, published 1562
"It is an article of faith that Mary is the Mother of the Lord and still a virgin.... Christ, we believe, came forth from a womb left perfectly intact." Martin Luther, Works of Luther, Vol. 11, pp. 319-320; Vol. 6, page 510.
"I firmly believe that Mary, according to the words of the gospel, as a pure Virgin brought forth for us the Son of God and in childbirth and after childbirth forever remained a pure, intact Virgin." Ulrich Zwingli, Zwingli Opera, Vol. 1, page 424.
(Polycarp) Actually, you are incorrect.
Actually, you didn't pay attention. I must assume you are honorable and "accidentally" missed the highlighted passage:
"...but Marian philosophy is, in Protestant thought, strange--because there is absolutely no mention of St. Mary being emmaculately conceived, a perpetual virgin, or bodily assumed into heaven anywhere in Christian Scripture.
That is, unless you have a different interpretation of Scripture.
As meandog pointed out, the writings of these men are not to be considered Scripture.
These men were practicing Catholics, attempting to reform a corrupt Church.
They were, at the least, just as Catholic as the SSPX.
Are the SSPX Catholic?