Church convert it to synagogue

Igros Moshe (OC. I #49) Question: A Catholic church which was destroyed in a fire more than 26 years ago and then was rebuilt as a school which was destroyed 3 years ago and only the brick walls remained, is it permissible to buy it and make it into a synagogue? Answer  This that it is customary in America to convert churches into synagogues is that they rely on the ruling of the Magen Avraham. However I don’t approve doing this since it uses something disgusting for a mitzva.. I am not saying that those already converted are prohibited. The importance of using something disgusting is only to avoid it but not to prohibit that which has been done. However, in this case where it was destroyed already there is a basis for leniencies. It seems that it is best that when building it until it is changed that one should not sanctify it as a shul but treat it as a normal building. Only after it is finished than it should be sanctified