I will not hire someone who holds this view, straight up. It's the only technical belief (aside from crazy things like don't care about quality) I can think of that would instantly disqualify a candidate in my mind. Everything else feels negotiable and perspective-relevant, but not this.
It's such a massive waste of time to try and rewrite functionality that already exists elsewhere, and an inability to trust other people is a huge, bright red flag when it comes to working with others on the team.
Being very selective of which libraries you use? Sure, fair. We can talk about various lines and where to draw them, but categorically denying library use? That's unacceptable.