what I can make out so far from that verse is that from the days of John the Baptist.. until now.
from John the Baptist until when Jesus is talking could only be one year time.
so Jesus was talking about around 1978 years ago
lasting for only a year, so this must be studied in that way.
I can only speculate that what Jesus meant is that violent people try to take kingdom of heaven by force without God's gift of Jesus and grace. but want it for themselves freely without repentance nor love and belief in God and His Messiah.
I am only speculating..