If the Restrainer is the Holy Spirit, then when the Restrainer is removed,... there still are a remnant of those who will believe in God through faith in Christ on their own volition.
Ummmm, say what?! The Holy Spirit is removed, and yet people come to faith? All on their own?
How's that supposed to work?
In the same fashion that OT believers came to faith in Him. Their believing is also dependent upon their will.