i have just read through the whole thread and you say several time this has been medically recommended by your doctor for your constipation but my opinion is this is just a smart (?) back track because i kept going back to your original OP and this is what i read
"I ( as in YOU) just ( as in today right before you posted) decided that since today is my due date
and there is no signs of little man arriving ( that doesnt say constipation to me, that say, im being impatient) im doing the castor oil mixed in a milk shake "
if you were truly recommended this by your doctor and doula then you would have just said you were doing it for the constipation and would not have even mentioned it helping your little man arrive, yes i know you said it would be a bonus if that happened as well as shifting the constipation but again i think you were just covering your back when you saw the majority of people not supporting you