The most recent crosser, 105, had been found in Maverick County, no ID, no fingerprint match, and his DNA had been sent for testing. The 104th crosser was identified quickly: a 41-year-old from Mexico whose family was working with the consulate to bring home his remains. The 103 crossers who had come before them had their own sad endings or non-endings. There was a man whose entire family lived in North Carolina, who had been trying to travel to join them, and instead of a welcome party they ended up having a funeral with an urn of ashes. There was another man who was found with nothing but a roll of U.S. bills, all $100s, and a love letter in English that was too decomposed to read much of except for the last line, “I can’t wait for you to hold me again.”
Sorry Jon, but you’re wrong

I just read an EW interview in which Jon Bokencamp said the following:

Red values loyalty above all else, and Mr. Kaplan betrayed him in the most impossible way. Remember, Reddington killed Newton Phillips in season 1 by suffocating him with a plastic bag from a funeral urn. He shot an old woman (Diane Fowler) after she betrayed him. Hell, he shot Pee Wee Herman! The man is ruthless. In Red’s mind, Mr. Kaplan had to go.

Except this was nowhere near the same thing. Newton was coerced and bribed and as a result Luli died. Diane Fowler was never loyal to Red, and she had a hand in Luli’s death, so yes she had to go. Mr. Vargas attempted to kill Dembe and set up Red and Liz to either save his own life or for money.

What Kaplan did hasn’t cost any of Red’s people their lives and it was following a primary order of Red’s: Protect Elizabeth. The idea that Red would feel he had to kill his oldest friend for trying to protect the person he loved most is hard for me to believe. Red does appreciate nuance in circumstances and has shown restraint when it suits him. 

He didn’t kill Madeline Pratt when she set him and Liz up for the theft of the statue. As far as we know, he hasn’t killed her for handing him over to the Kings.

He didn’t kill Dr. Orchard for forcing Liz through a dangerous memory retrieval procedure.

He didn’t kill the Major for sending Red ‘defective merchandise’ and allowing Tom to switch allegiance to Berlin.

He didn’t kill the FBI executive with dangerous knowledge of his relationship to the FBI who exposed him to the people at the Shell Island Retreat.

So yes Jon, Red is ruthless, but we’ve had reason to hope he’d come up with a fairer punishment than death.