Just about every argument we look at makes use of a "conditional."  A conditional is a statement of this form:

If P, then Q.

The P here is called the antecedent of the conditional. The Q is called the consequent.

For instance, the Abe the Abuser argument against 10C contains this line:

"If 10C is true, then Abe's acts of beating up this children are morally permissible."

If can be tricky to explain why a conditionals is true.  Notice that the conditional above about 10C does not say that 10C is true.  It also does not say that Abe's acts of beating up this children are morally permissible.  Rather, it says that if 10C is true, then Abe's acts are morally permissible.  Thus, it is possible to agree with the whole conditional even though you do not agree with either the antecedent or the consequent.  Thus, in order to explain why the above conditional is true, it will do you no good to try to explain why 10C is true, or to try to explain why Abe's acts are permissible.

What you need to do is explain the connection between 10C's being true and Abe's acts being permissible.  To do that, do these two steps:

1. Assume that the antecedent is true.
2. Show that, given this assumption, the consequent would also have to be true.

If you do these two steps, you will have explained why the whole conditional is true.  When you do this, you are not committing yourself to believing that the antecedent is true.  Rather, you are merely assuming it to be true for the purposes of explaining why the whole conditional is true.

So here is the rationale behind the conditional about Abe (i.e., the reason it is true):

"Let's suppose 10C is true.  Well, 10C is the view that an act is morally right if and only if it does violate any of the Ten Commandments.  So, given the assumption that 10C is true, it follows that any act that does not violate any of the Ten Commandments is morally permissible.  Abe's acts of beating up his children do not violate any of the Ten Commandments.  He never beats them up on the Sabbath; he never murders them; he never takes the Lord's name in vain while he is beating them up; etc.  In short, he never violates any of the Ten Commandments.  Therefore, these acts are morally permissible, given the assumption of 10C.

Just to see different ways of doing it, here is another excellent rationale:

10C says that any act that does not violate any of the Ten Commandments is morally permissible.  10C thus implies that Abe's acts of beating up this children are morally permissible, because in doing so, Abe never violates any of the Ten Commandments (he never beats them up on the Sabbath; he never murders them; he never takes the Lord's name in vain while he is beating them up; etc.).