Maybe we should learn to live comfortably with brother marrying sister, or pedophilia.

Don't we all have moral  boundaries that we think should be applied to other people?

Cardinal Burke has his idea of what such boundaries should be, yes.  But don't you?

Surely you have some.  

So the debate shouldn't be based on the notion that it's wrong to have moral boundaries for others people.    Even the most radical progressives have their own ideals of what behavior by others is right and wrong.

Burke's ideas (like Francis') are based on a set of reasons, that are based on the good of everyone. 

That they disagree shouldn't be reduced to some variation of "rules for everyone bad, no rules for anyone good."