This view is not fideism; the Spirit's internal witness is genuine evidence, and the Spirit converts — not arguments

Fideism is belief without any basis — no witness of the Spirit and no evidence. Winger's view involves genuine epistemic content: the inner witness of the Holy Spirit is evidence and reason for belief. He simply cannot show it to others. Also: arguments and evidence do not convert people — the Holy Spirit converts. But the Spirit can use arguments and evidence as part of someone's path to Christ. All major apologetic approaches agree on this last point.