She claims to be the "defender of the [Christian] faith" so the New Testament would demand staying in as nationalism is very much opposed by James and Paul (and James' views would suggest that Jesus was anti-nationalist too though the actual quoted comments of Jesus would require interpretation to determine if he actually felt Canaanites were lower peoples or if he was just using colorful speech to make a larger point toward moving away from nationalism).
The head of the Anglican church had the audacity to claim that there is no position the Bible takes on the issue. I would classify that as a lie. The Old Testament is nationalistic and the New testament is anti-nationalist (starting with Acts and then after).
Okay, so that's what she is "supposed" to say... what is she actually saying?