You understanding of Catholicism is sorely deficient. The word "ignorant" is fitting but cannot be appropriately applied on this forum.
Are Catholics known to come to the defense when something vile has been posted here about Joseph Smith or Alexander Campbell?
I really don't know since I can't recall something vile being posted about them. But I suspect not since Joseph Smith and Alexander Campbell are uniquely associated with specific denominations. However, the BVM is the Mother of Jesus and is common to all who are Christians. The Mother of Jesus should be respected by all Christians, but rather there are those "Christians" who do just the opposite.
Your suspicions are correct - in my experience, Catholics never come to the defense when vile postings are made against individuals or beliefs held important by other Christians or by Mormons.
Why should you take umbrage when no one comes to your defense, when you don't offer the same courtesy to others?