Rabbi Yaakov Ariel’s criticism is about the very existence of private kashrut supervision outside the Chief Rabbinate, a criticism that is well known. And suddenly all those who have been dismantling the Rabbinate (the Badatz kashrut certifications, their private religious courts, conversions, and so on) are placing their hopes in the Rabbinate — after having destroyed it from within! Rabbi Ariel wants to return to a state Rabbinate for everyone, which doesn’t seem very likely to me in the near future.

But from there to the principled claim that food under Tzohar’s certification is not kosher?! That is simply incorrect.
You can say that he does not rely on it, but “not kosher” — that is already a political statement.

Now that we’ve already entered the discussion, it’s interesting why the Badatz organizations, which are also private systems, receive approval from the Rabbinate and Tzohar does not. After all, the Rabbinate could also have given approval to Tzohar’s kashrut, and then they would be exactly like the Badatz organizations and everything would be wonderful, no? That way our monopolistic regulator (the oxymoron that describes the Rabbinate’s conduct and status) would be preserved, to the delight of God and man. Ah, I forgot: unlike the Badatz organizations, Tzohar is not kosher — definitely…

With all due respect to the Rabbi, I object to the sharpness and the cynicism. It does not honor a principled and serious discussion.

First, there is no serious discussion here at all. If there is — in my sins, I failed to notice it.
Second, there was no cynicism here at all. I am claiming that Rabbi Ariel lied. It seems to me that in the dictionary, saying something untrue = a lie. Does your dictionary say something else?

Since when do the Badatz organizations receive certification from the Rabbinate?

They do not receive certification from the Rabbinate. The use of the term “kosher” is permitted by law only for something deemed kosher with the Rabbinate’s approval.