When I was in college, I had professors try to deconstruct and demolish Christianity, and they did so primarily through "morality puzzles"
You are a Jewish mother of an infant child
You and 50 jews are hiding in a basement
The nazis come to the door
Your baby starts crying...what would you do...
And then their statement: "see, sometimes it is okay to kill children"
But these "morality puzzles" are, in a word, dumb
The option a Catholic should take in the above "puzzle" is "I'm not killing my child. If my crying child leads the Nazi's to find us, and then, when they find us, they also then decide to kill us, guess who that is on...THEM."
People who try to deconstruct the Church's moral teachings are always using these puzzles, but they are always ridiculous.s
A friend recently asked me one of these puzzles in response to my statement that I don't see how I will be voting for president in 2016
"A car is burning
You can only save 3 of the 4 people
1) call 911 (takes too long, all will die)
2) Grab people out yourself knowing that you can save at most 3 persons
or 3) do nothing and watch them all burn to death"
This puzzle, again, presents false options
No one, in the above scenario, would know any of the parameters as the person has laid it out
I would call 911 because no angel would be standing there saying "Don't call 911, it won't work"
I would then run and start trying to pull people out because again no angel would be there saying "you can only save at most 3 of the 4"
I would also note that the above choice would be one I think I would make, but it would be what the Church would consider "heroic virtue" in that you are not REQUIRED by the Church or God's laws to run toward a burning car and try and save people
So to answer the question, this is the way people try to deconstruct Catholic moral reasoning, but it is deeply flawed