• āśramān — spiritual communities, hermitages
  Āśrama = a place of disciplined life around a guru. To defile an āśrama is to attack the very nodes through which Vedic order propagates. The asura targets infrastructure, not just people.
• ṛṣi-mukhyānām — of the foremost sages
  Ṛṣi-mukhya — the leading seers. Their āśramas are not random forests but the lineages that hold up Vedic dharma. The chapter is showing dharma under cumulative assault from one source.
• agnīn-vaitānikān — the three sacrificial fires
  Vaitānika = the three Vedic śrauta fires (gārhapatya, āhavanīya, dakṣiṇāgni). To pollute them with excrement is to attack the very channel between humans and devas. Maximally asuric inversion of yajña.
• śakṛt-mūtraiḥ — with feces and urine
  Compound: śakṛt (excrement) + mūtra (urine). The grossest available form of pollution — the asura performs an anti-yajña, offering filth where ghee belongs. SB does not flinch from naming evil precisely.
• khalaḥ — wicked one, scoundrel
  Khala — a classical Sanskrit epithet for the deliberately malicious. Bhagavad-gītā 16.7–18 names the āsuri-prakṛti in detail; Dvivida is the chapter's living catalog of those traits.

• What sacred space or practice in my life have I let be 'polluted' by neglect or contempt?
• How do I guard the small altars of my life against careless damage?

A wicked man finding a clean hearth thinks first to defile it — Dvivida picks the ṛṣis' yajña-fires precisely because they are pure. Asuric mind is allergic to brightness; it goes for what offends sat the most.