Well Notice how I mention the word Soft Counter. It is not meant to demolish light vehicles or any vehicles but it does something which can help ward off a hard push or preventing them from chasing your retreating units (T-70 is rather good at picking off squads that are retreating).
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Being able to only soft counter cheaper light vehicles is not a strong point but rather a weakness, even members of the MOD realized that the unit is not that good vs vehicles.