I don't think Zelenskyy is a saint - far from it.

However this is one of the weakest possible grievances you could raise because Putin also released rapists and murderers from prison to raise manpower, most famously during the spring 2023 Bakhmut offensive. There is no moral highground on that point.

Actually, this is actually a near universal issue with Russian grievances against Ukraine. Virtually any grievance that Russia can claim against Ukraine, Ukraine can claim that exact grievance back at equal or greater measure.