They always respond, “She’s no better than us.” Lord have mercy!
Although it's easy to interpret this as disrespect (and oftentimes, it probably is, especially as part of rhetoric designed to provoke Orthodox/Catholic opponents), I think that on a deeper level it's reflective of the notions of egalitarianism intrinsic to virtually all forms of Protestantism.
In the Protestant paradigm there's really no notion of degrees of holiness or sanctity, you're either Saved or Damned. So saying that somebody should be venerated just doesn't make sense in their spiritual worldview because salvation is a legal status which is divorced from behavior and one's sanctity (or lack thereof.) When that's their paradigm, it's like trying to convince a loincloth-clad Amazonian tribesman that snow and polar bears exist. But I don't think it's overstating things to say that sometimes these harsh reactions may be the instinctive response of those who feel threatened, on a subconscious level or not, of what all this represents.
Where it gets really interesting is considering how much this sort of spiritual egalitarianism parallels with notions of egalitarianism in Western Civilization, and their extreme endpoint in the rhetoric of the Social Justice Warrior and all the talk about "equity" and equal outcomes. I think you could make an interesting argument that this is the ultimate endpoint of notions of egalitarianism that emerged in the Reformation and philosophical movements that followed in its wake.
On a more practical level, this type of objection is pretty silly because these stakes are higher for the Mother of God than anybody else called by God. What girl wouldn't immediately fear being considered a whore and adulteress, as it could easily appear to the outside world, if she the virgin conceives? There's a very high likelihood you'd just get stoned to death for adultery per the Mosaic law, and at the very least, kiss your comfortable arrangement for Joseph to marry/provide for you goodbye. Best case scenario, everybody considers you a whore the rest of your life and whatever honor and place in society you have is turned to shame. Without an astounding level of faith in God, Mary would have immediately run the other way, regarding the angel's tidings as bad indeed. Instead, she wholeheartedly embraces the call. Compare to all those people elsewhere in Scripture - Jonah, Zechariah, Sarah, Gideon, to name a few - who react incredulously to far less precipitous tidings than this. On the basis of the Scriptural texts alone, it's quite obvious that Mary is special indeed, if you have the eyes to see it.