Friend they were already blind. Blind is blind. This idea that He had to blind them more to make room is no place supported in scripture.
He is not blinding them. They are blind because of their own free will. They are in fact willfully ignorantly blind. (2Peter 3:5)
What is happening is that they have chosen not to believe, had no love for the truth, and He is locking them in their own free will choice. (2Thess 2:10) They could have been saved if they would have chosen to but because they did not want the truth God locked them in hardness.
Election and free will both working together.
We are not far apart on this, I also agree that God leaves some in their willing blindness. The disciples did not understand Jesus's parables much better than the scribes and Pharisees, but the difference was they would always seek and ask Jesus later to explain them. They chose to listen and learn from the Father (John 6:45)
Jhn 6:45 It is written in the prophets, And they shall be all taught of God. Every man therefore that hath heard, and hath learned of the Father, cometh unto me.
Election is not a mystery to me, I believe God elected those he knew would believe on Christ. The scriptures say we are elect according to the foreknowledge of the Father. The scriptures clearly say Jesus knew from the beginning who would believe not, therefore he also knew from the beginning who would believe.
Jhn 6:64 But there are some of you that believe not.
For Jesus knew from the beginning who they were that believed not, and who should betray him.
Seems very plain to me, no mystery at all. When a person understands this view it explains a lot of difficult scripture, such as John 10:26.
Jhn 10:26 But ye believe not, because ye are not of my sheep, as I said unto you.
Jesus knows these persons will not believe, because he knew from the beginning who would believe and who would not (foreknowledge). Because it is known they will not believe, they were not elected and are not Jesus's sheep.
The next verse confirms this view.
Jhn 10:27 My sheep hear my voice,
and I know them, and they follow me:
Note the order, very important. First, Jesus's sheep hear his voice, and then afterwards he knows them. This is speaking of foreknowledge.
Jesus could declare who his sheep were and who were not, because in God's foreknowledge he always knew who would believe and chose or elected them.
This is the foreknowledge view of election.
This gets a little confusing, but God does not know any person in an intimate way until they actually believe.
Gal 4:9 But now, after that ye have known God,
or rather are known of God, how turn ye again to the weak and beggarly elements, whereunto ye desire again to be in bondage?
God does not know a person in an intimate way until they actually believe in time as this verse shows, but in his foreknowledge he knows these persons from the beginning as also shown in scripture.
This is not easy to comprehend, but this is what the scriptures show.