Thank you for your thought provoking question!
I trust you are aware of the teaching of Christ in Matthew chapter 13? I suggest you look at that chapter,in either the KJV or ESV, and notice that the Kingdom of Heaven is taught by Christ to consist of the True Converts and False Converts. Thus you see examples, like of the fisherman that is like the KIngdom of Heaven.He casts out his nets and gathers many fish; some turn out to be bad and are thrown away,some are good and kept. Also mentioned in this teaching is the Sower that sowed good seed. When it sprouted, the farmer's workers noticed that some of the seed grew up to be good wheat,while some of it was "weeds". The workers asked the farmer if they should pull up the "weeds", but he said no,let them grow together until the harvest,when they will be seperated,some to burn,and some to be gathered in. This is also a teaching of the Kingdom of Heaven.
When you see "Kingdom of Heaven" in the Bible, as far as I am able to understand, it ALWAYS refers to "Christianity", those who could be True Christians or False Christians. All Greek Orthodox belong to the Kingdom of Heaven.All Catholics belong to the Kingdom of Heaven. All Mormons belong to the Kingdom of Heaven. All Jehovah's Witnesses,Baptists, etc etc. Are they indeed Christians or are they deceived?
Therefore, when the Bible says that the violent have been taking the Kingdom of Heaven by force, I am reminded of the Crusades. Many "Christians" sought to work for the Kingdom of Heaven by forcing Jews,Muslims, and pagans to become "converted" at the tip of a sword or suffer instant death. This is the violent taking the Kingdom by force.Also,think of Cortez in Mexioco, El Cid in Spain amongst the Moors, the Teutonic Knights against the pagan Poles, and you have the idea of taking the Kingdom by force,
This does not imply that Christ has given up the Kingdom of Heaven...on the contrary, His Kingdom of God has never been under any danger. No one cometh unto the Father but by Him.
While ALL who name the name of Christ are Kingdom of Heaven, only the Truly Converted are in the Kingdom of God.
Don't forget to read Matthew 13! With this teaching of the Kingdom in mind,it will give you fresh insight.
Your Brother,
Julian of York
John 15:9