It certainly is suspicious that people were fired "for performance reasons" when the company is unable or unwilling to provide the performance data that would support that assertion.

But, on the other hand, these employees were probably "at will", so the company does not need to give any reason, or even to publicly justify the firings in any way. So it could be that "performance" is the lie that they believe to damage ongoing recruiting efforts the least.

Or it could be that they have determined individual performance assessments to be useless in the face of the more objectively measurable department-wide performance numbers.

All I know for certain is that I won't be sending them any applications or resumes until they can elucidate their motives behind this.

The simplest explanation is that the company isn't making money and investors are getting antsy about bankruptcy.