The Virgin Mary

In keeping with our Christmas theme here at Upstate Lutheran:

I can understand why a lot of protestants have problems with the excesses of Marian dogma and practice within the Roman Catholic Church, but why must so many protestants go out of their way to insult her? Is it really any business of ours what she and her husband did together?

I definitely lean toward the "ever virgin" end of the argument, but I fail to see why the question elicits such strong condemnation from protestants. I mean, just because the RCC says Mary was ever virgin does not make it untrue, does it?