Yeah they can be taken out, I've got them on my bike. An unfolded paper clip might help you fish the cable out the other end, or a small cable tie feed through the hole perpendicular to the cable, before the cable is put in, so that both ends are poking out of the hole, then thread the cable through, pull the cable tie out, then back the cable off until the end pokes out of the hole. Then send your frame builder an angry email as to why they didn't use a tiny tube to like the ports together.
Yeah they can be taken out, I've got them on my bike. An unfolded paper clip might help you fish the cable out the other end, or a small cable tie feed through the hole perpendicular to the cable, before the cable is put in, so that both ends are poking out of the hole, then thread the cable through, pull the cable tie out, then back the cable off until the end pokes out of the hole. Then send your frame builder an angry email as to why they didn't use a tiny tube to like the ports together.