The following is a good reason of why Protestants find the Roman Catholic dogma of the intercession of Mary to be inherently dangerous and, in the example here, utterly blasphemous.
Now I know, I know, it will be defended according to all manner of apologetic attempts to justify this kind of theology in light of Scripture, or tradition, or magisterial decrees. But I would ask your consideration in order to better understand why we feel this must be utterly rejected. From St. Alphonsus Liguori’s The Glories of Mary:
Mary not only assists her beloved servants at death and encourages them, but she herself accompanies them to the tribunal seat of God. (p. 103)
With reason does an ancient writer call her “the only hope of sinners,” for by her help alone can we hope for the remission of sins. (p. 83)
He falls and is lost who has not recourse to Mary. (p. 94)
But now, if God is angry with a sinner, and Mary takes him under her protection, she withholds the avenging arm of her Son, and saves him. “And so,” continues the same saint, "no one can be found more fit for this office than Mary, who seizes the sword of divine justice with her own hands to prevent it from falling upon and punishing the sinner. (p. 124)
St. Anselm, to increase our confidence, adds, that “when we have recourse to this divine Mother, not only we may be sure of her protection, but that often we shall be heard more quickly, and be thus preserved, if we have recourse to Mary and call on her holy name, then we should be if we called on the name of Jesus our Saviour,” and the reason he gives for it is, “that to Jesus as a judge, it belongs also to punish; but mercy alone belongs to the Blessed Virgin as a patroness.” Meaning, that we more easily find salvation by having recourse to the Mother than by going to the Son. (p. 136-137)
And shall we scruple to ask her to save us, when “the way of salvation is open to none otherwise than through Mary.” (p. 169)
[St. Peter Damian] addresses her in these words: “All power is given to thee in heaven and on earth, and nothing is impossible to thee who canst raise those who are in despair to the hope of salvation.”(p. 180)
“At the command of Mary all obey - even God.” St. Bernardine fears not to utter this sentence, meaning, indeed, to say that God grants the prayers of Mary as if they were commands…Since the Mother, then, should have the same power as the Son, rightly has Jesus, who is omnipotent, made Mary also omnipotent; though, of course, it is always true that where the Son is omnipotent by nature, the Mother is only so by grace. (p. 181-182)
“Be comforted then, O you who fear,” will I say with St. Thomas of Villanova: “Breathe freely and take courage, O wretched sinners; this great Virgin, who is the Mother of your God and judge, is also the advocate of the whole human race; fit for this office, for she can do what she wills with God; most wise, for she knows all the means of appeasing him; universal, for she welcomes all, and refuses to defend no one.” (p. 198)
[Prayer of St. Ephraim:] O Immaculate Virgin, we are under thy protection…we beseech thee to prevent thy beloved Son, who is irritated by our sins, from abandoning us to the power of the devil. (p. 273)
The holy Church herself attributes to the merits of Mary’s faith the destruction of all heresies: “Rejoice, O Virgin Mary, for thou alone hast destroyed all heresies throughout the world.” (p. 566)
