Why do some Christians still use the KJV instead of translations written for people in the last century.
There are so many words in KJV that are no longer in use, or were never in use in the furst place! They were "invented" for the original KJV (Read histories of the English language)
Back to the passage.
Why these people could not be a part of the assembly of the Lord was that they were of no use to the building up of the Jewish people. They could not have children. Israel was a very small country in population compared to those around and they could not afford to have men unable to have children.
Hence other sexual issues come to light, e.g homosexuality, and as some say, the railway station principle, always pulling out in time! (Sorry about the bad joke - I am well, or badly know, as telling bad jokes)