What is the name of that logical fallacy wherein the de-platforming of a harmful lie is construed as evidence of suppression of a truth?

What is the name of that logical fallacy wherein the de-platforming of a harmful lie is construed as evidence of suppression of a truth?

Example:

Little Johnny starts a campaign to convince everyone in class that math homework is a diabolical deception designed to melt their brains. Johnny’s claims are patently false, but difficult to disprove, and wildly compelling for the other students. The idea gains traction, and the class mutinies.

The teacher, now in damage-control mode, removes Little Johnny from class. As she’s walking him down the hall to detention, Little Sally stands up to address the class, saying, “Isn’t it odd that the teacher would silence Little Johnny instead of arguing with him? This must mean he was right!”

 
What logical fallacy is Little Sally guilty of?

I've been reading about the following, but not sure how to apply them here:

• Furtive Fallacy?


• Cancelling Hypothesis Fallacy?


• Conspiracy Theory Fallacy?

Note:   I'm asking about Little Sally's reasoning -- not Little Johnny's claims .  I've asked this question in other forums, and for some reason people tend to focus on Little Johnny's claims.  I'm not asking about Little Johnny's claims.   I think we could replace Little Johnny's claims with virtually anything and still have the same conversation about Little Sally's reasoning.  I.e. even if Johnny's claims were true, Sally's reasoning (I think?) is fallacious.