When people tell you its bad but they have not changed their mind ....

Let me argue as Devil's Advocate here. The discussion on youtube is about one effect of brexit downside only. If the lady who would still vote Brexit was entirely happy about everything else to do with Brexit, except this one effect, why should she junk everything she sees as good just because one aspect is bad? Nothing is perfect.

I do not agree with her but I can see where she is coming from and why it seems a completely rational decision.

Do not let your own strongly held views come between you and understanding your opponents.