That’s a Wescott & Hort talking point: which is their assumption only. No evidence.
Not when faithful God-fearing scribes handled the copying process. This is where the Spirit guides us into truth; both scribes and readers.
The English language hasn’t changed much in recent years, yet translations keep being made. And by changing words and leaving out scriptures from other manuscripts, how does that “give us the clearest and best understanding” of the text?
Spiritually compromised scholars from the 1800’s until now didn’t have spiritual discernment so they erred in following the wisdom of men when selecting what readings to translate and how to translate them. Thus they selected the worst manuscript witnesses and oftentimes did not even translate what they had very well.
Pedants without prudence.
There is plenty of evidence to show that there were/are scribal errors in the early sources, as well as errors in the early printed versions. There are even sections in the KJV that are questionable: the "long ending" of Mark, the story of the woman caught in adultery, and the addition of the words to Romans 8:1. They have very little evidentiary support in the earliest and best manuscripts.
Do you actually believe that "spiritually compromised scholars from the 1800’s until now didn’t have spiritual discernment". Really? How deluded can you possibly get????