Bhashya
स्थानकरणवैगुण्यात् असुरै पाप्मना विद्ध , वाग्वात्मापि सन्, मुख्यस्तु तदसम्भवात् स्थानदेवताबलीयस्त्वात् न विद्ध इति श्लिष्टम्— यथा वास्यादय शिक्षावत्पुरुषाश्रया कार्यविशेष कुर्वन्ति, न अन्यहस्तगता , तद्वत् दोषवद्घ्राणस- चिवत्वाद्दिद्धा घ्राणदेवता, न मुख्य ॥
In plain words
Because of flaws in their physical seats and instruments, speech and the other senses were pierced by the demonic evil. But the primary breath was not pierced, because that is impossible and because its presiding power is supreme. This makes complete sense. Just as tools like adzes perform their work when guided by a skilled craftsman, but not in unskilled hands, so the deity of smell was tainted through its association with a flawed organ, but the primary breath was not.
Close to the Sanskrit
Due to the defect of locus and instrument, speech and self being pierced by demons with evil, but the primary not being pierced because of its impossibility and the superior strength of the locus deity — this is coherent. Just as adzes and other tools resting on trained persons perform specific work, not when gone to another's hand, similarly, due to association with a flawed smelling organ, the olfactory deity is pierced, not the primary.