I don't believe this is always true.
One example I gave already was the Pharoah's heart being hardened. Another example would be in our current era, The Age of Grace.
Rom. 8:29 For whom He foreknew, He also predestined to be conformed to the image of His son,... (30)Moreover who He predestined these He also called; whom He called, these He also justified; and whom He justified, these He also glorified.
A different example would be the Millennial Reign where I believe man is given free will and the result was rebellion.
There is a further explanation in Rom. 9:13-23, especially v. 18 and 19.
"So then he has mercy on whom He desires, and He hardens whom He desires. You will say to me then, 'Why does He still find fault? For who resists His will?'"
It did not work when Adam pointed the blame back to God for his sin, "the woman whom Thou gavest me...".
It will not work for us to say "Lord, you made me this way."
No biggie either way. I think it comes down to the Lord being the Lord of time and seeing the end from the beginning and the beginning from the end.
Before God removes the heart of stone and replaces with a heart of flesh, how free is the will of man? His thoughts are evil continually. He has no faith, and can have no faith of his own doing and therefor finds it impossible to please God. His will is bent towards sin, so much that it is said the he is a “slave to sin”. Not very free if you ask me.
But in the sense that man makes his choices based on his own desires, yes man is free. Just his “desirer” is corrupt.
I look at it this way, in a broken analogy. At 9:30 pm I’m watching a show on TV. A commercial comes on for a juicy cheeseburger. All of a sudden I make the freewill decision to get up and leave the house to go to that establishment and get a burger. I made a freewill choice...that resided inside a set of circumstances created by advertisers who have spent billions to get to know the inner me and what makes me tick.
In a similar way, God knows me so well, better than I know me, and can create the correct circumstances in my life to allow me to make the freewill decisions and yet still be subjected to His sovereignty and the working out of His will through His providence.
Pharaoh made every choice of his own freewill, and yet was directed by God to those decisions due to God knowing what it would take for Pharaoh to be hardened. To fit it in my analogy, the plagues were commercials, done by an all-knowing, always successful God.