Although there are no clear signs that Mr. Trump has increased the quantity of abuse he levels at his opponents,
Exactly. “Mr. Trump could potentially alienate an undecided audience uncomfortable with his coarse rhetoric.” Why would the NYT warn Trump that he could alienate voters unless he tones it down? Of course the opposite is true. They want Trump to stop calling Kamala comrade Kamala. The want to disarm Trump’s humor and sarcasm because they are effective tools.