No, Mike, it's not a PoV. cosaint isn't the Irish for "security", and the fact that there might be certain circumstances where it doesn't really matter whether you say "security" or "protection" or "defense", doesn't mean that these words are always interchangeable, in English or in Irish. While "security against computer viruses", "protection against computer viruses" and "defense against computer viruses might all be interchangeable, here are some examples of places where cosaint and cosanta are used that clearly can't be translated as "security":
Aire Cosanta - "Minister for Defence"
an Coimisinéir Cosanta Sonraí - "Data Protection Commissioner"
an Coinbhinsiún chun Cearta an Duine agus Saoirsí Bunúsacha a Chosaint - "European Convention for the Protection of Human Rights and Fundamental Freedoms"
an Cumann Ríoga um Chosaint Éan - "Royal Society for the Protection of Birds"
an Institiúid Éireannach um Chosaint Raideolaíoch - "Radiological Protection Institute of Ireland"