LCR Honda's Zarco and Aprilia's Espargaro were battling at the outer reaches of the points in Sunday's grand prix at Jerez when they collided at Turn 5 on lap 10.
The incident was placed under investigation by the FIM stewards panel, but no further action has been taken following a hearing involving both riders.
However, Zarco says double 500cc world champion Spencer – who has helmed the FIM stewards panel since 2019, which was created in the wake of the infamous Sepang clash between Valentino Rossi and Marc Marquez to take penalty judging out of the race director's hands – is not fit for his position.
In a lengthy attack, the Frenchman said at Jerez: "Me, in my opinion, because I went to the race direction and Freddie Spencer was watching the action with us.
"And it seems he was looking at me like he wanted to know what I wanted. He wanted for me to complain about Aleix.
"I said 'I will not complain' but I said to him he is not good for this job because he doesn't take the right decision in the right moments.
"So, 'don't ask me what you have to do'."
When it was put to him it sounded like Spencer was waiting for Zarco to decide what should be done, he added: "It seems it is like this. I went to the race direction and he was looking at us, because I was with Aleix, like we are two children and they want to do a moral lesson.
"But 'no Freddie, maybe you have a lot of passion but you don't take the right decisions. You are not in the right place', and we need to move things on because the action of Brad [Binder] yesterday [in the sprint] – if there is not [Marco] Bezzecchi [on the outside] – can happen because Pecco [Bagnaia] was surprised by Brad, he picked up the bike and he hit Bezzecchi.
"So, in that moment there is an opportunity for Brad because also Brad could take into consideration that [overtaking] three can be tricky.
"So, accept this and control. And at this moment Aleix agreed with me.
"Anyway, the riders are working to have this group together to have the right to speak and then get the right people to make the decisions.
"Aleix today, it's just a pity that we crashed and just everything after was wrong. And I repeat Freddie Spencer is not the right guy in this place."
Zarco says he was "kicked out" of race direction for his outburst.
For Espargaro's part, he says that he locked the front wheel at Turn 5 which sent him down and into Zarco – but was unhappy with the battle with the Frenchman up to that point.
"I was very unhappy because I said to Johann, we are in P14, he hit me three or four times, you need to have more respect," he said.
"He said it's my way of riding, overtaking like this. Okay, it's not my way of riding. This is why to avoid the contact I locked the front and I crashed.
"Because the easy thing for me at that corner was to touch him a little bit. We saw that yesterday no penalty coming in this. But it's not my riding style.
"I don't want to do that. I locked the front to avoid the contact.
"This is what I said to Johann. And he said, okay, I understand you, but then Johann was really angry with all the race direction panel for other actions of yesterday and he doesn't hide the emotions."
Inconsistency in the application of penalties was a key complaint amongst riders last year, while others – most notably Cal Crutchlow – have since 2019 been extremely vocal in their dislike of the job Spencer has been doing.
