You are for open borders everywhere.
That's not relevant to the question of EU membership at the moment.
As it happens, I think the EU should be more open but if we leave it, I'll never have the opportunity to change its current policy. More to the point, it might suddenly become closed to me and many other Brits like me who sometimes work in continental Europe.
This is a problem that Leavers seem to ignore. i.e. anything we can do to Europe they can do to us but with bells on. So, foe example, yesterday on Today, some moronic Leaver was arguing that the EU prevents us from deporting foreign convicted criminals which means we won't be safe in our beds. He neglected to mention that the same rules also prevent other countries deporting British criminals back to the UK.