So, I assume in your mind a clearer rephrasing of Matthew 18:9 would be:
"And if thine eye offend thee, pluck it out, and cast it from thee: it is better for thee to enter into life with one eye, rather than having two eyes, and casting oneself into hell fire."
Sorry, but this simply doesn't follow from
"And if thine eye offend thee, pluck it out, and cast it from thee: it is better for thee to enter into life with one eye, rather than having two eyes to be cast into hell fire."
The "to be" too strongly implies a doer other than the self; particularly when the object of the "to be" is a disagreeable one.
Why would a person want to put themselves into hell fire? They wouldn't.
Nope, your reasoning simply fails here. God is the one casting/throwing people into hell fire.
You are free to believe what you want, but you are inserting your own opinion into the text.
Try to reason it out logically:
Who is supposedly "cast" into hell fire?
-The wicked.
Why are they wicked?
-Because they decided to commit sin rather than obey God and keep His commandments.
Did someone force them to choose sin over righteous living?
-No, they chose it all on their own.
Were they warned about the eventual consequence of committing sin?
- Yes, God sent many servants to the world, including His Son, to teach these things and to have them written.
Do the wicked want to go into hell fire?
-No, they do not.
Do the wicked fulfill the requirements to enter into Heaven?
-No, they do not.
Are the wicked worthy to enter Heaven?
-No, they are not.
Did anyone force them to be unworthy?
-No, they became unworthy as a consequence of their sinful living.
If they cannot get into Heaven, where will the wicked go?
-A place prepared for them outside of Heaven.
Did God force them to live sinfully?
-No, He did not.
Did God cause the wicked to be unworthy of entrance into Heaven?
-No, He did not.
Why can't God let them into Heaven anyway?
-That would make God a liar.
Can't God do whatever He wants?
-No, He is a Perfect Being and cannot do anything contrary to His nature, such as lying.
Who decided that the wicked would go to Hell?
-The wicked made the choice to sin and to rebel against God and to break His commandments which caused them to be unworthy of entrance into Heaven.
How are the wicked cast into Hell?
-Through their sinful actions they cast themselves into Hell.
Your argument about the "to be" is very weak. The "to be" is simply the future tense of the eyes being cast into hell fire in the "rather than" scenario. It is better to do one thing
rather than the other thing. It is similar to saying that the two eyes
will be cast into hellfire, in the future sense, except the Lord was using the "rather than" scenario. "It is better to go to Heaven with only one eye than
to be cast into hell fire with two eyes." It in no way implies a third party. It is simply a matter of future tense being used in a "rather than" scenario.
The wicked who cast themselves into hell fire do not
want to go there, but they did want to sin and rebel against God. They wanted to sin without receiving the consequences of such living. It is akin to those who
want to have sex outside of marriage, but they don't want to be committed to another person/have children or certain responsibilities etc. However, avoiding certain consequences this life throws at you is only possible here, where we are free to choose Good or Evil for ourselves. But when this life ends, we will be held accountable for our actions according to the Law and if we did not receive a forgiveness of sins through the Lord Jesus Christ, then there is only the one place where we can go and we put ourselves in that place by living in sin.