Except the reading isn't that. It misses out verse 15:
Outside are the dogs and sorcerers and the sexually immoral and murderers and idolaters, and everyone who loves and practices falsehood.
Hmm. Guess it might have something to do with being a nation of dog-lovers. Or maybe because it makes us uncomfortable thinking about this. Even worse is the missing out of verses 18 and 19:
I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues described in this book, and if anyone takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book.
Hmm, so excluding the words warning us of the danger of excluding the words.
We need to look out for this sort of thing in lectionaries. Yes, there can be a place for excluding verses where the narrative is impacted, e.g. Jesus tells a parable, then spends a few verses doing a healing or three, and then explains the parable, but this practice in the lectionary of missing out some verses is wrong.
When we get to 10 November, which is the Third Sunday Before Advent, the New Testament reading is II Thess. 2, but excluding verses 6 to 12:
And you know what is restraining him now so that he may be revealed in his time. For the mystery of lawlessness is already at work. Only He who now restrains it will do so until He is out of the way. And then the lawless one will be revealed, whom the Lord Jesus will kill with the breath of His mouth and bring to nothing by the appearance of His coming. The coming of the lawless one is by the activity of Satan with all power and false signs and wonders, and with all wicked deception for those who are perishing, because they refused to love the truth and so be saved. Therefore God sends them a strong delusion, so that they may believe what is false, in order that all may be condemned who did not believe the truth but had pleasure in unrighteousness.
Hmm - why do these lectionaries exclude verses?