If I were to take their words at face value, this group considers abortion to be murder. Because I don’t expect an argument of the form “if you don’t like murder, don’t do it” to have a good outcome, I would instead focus on the fact that in all other regards bodily autonomy is so important that we are not obligated to perform even safe procedures such as donating blood in order to save the lives of others, and indeed this respect for bodily autonomy (in the USA) also extends to organ donation after death being opt-in rather than opt-out.