While I’m sure this is true it’s unlikely Kerry said so in those words. If he did, he has zero political acumen. I’m guessing he does and this is a made-up attribution.
However, all’s fair in war and politics. I’ll hand him the sword to fall upon.
I was skeptical on first read as well. However, it might make sense if Kerry thinks he could regain the 2016 presidential nomination by throwing Hillary and Obama under the bus.
Since his entire scummy life has been geared toward achieving that goal, I would not put this past him.