The Virushi homeworld is a member of the Third Imperium. Virushi are Imperial citizens.
The Imperium understands the need to respect the philosophies of the various cultures and races that make up the Imperium. Hence, the Imperium recognizes and respects Virushi pacifism.
The Imperium provides the MILITARY DEFENSE needed to protect Virsash and the Virushi home system. Problem solved...
Non-GURPs.... the Virushi were originally introduced in a GDW JTAS article, so they originally appeared in Classic Traveller. Sorry, I do not recall the exact issue number, but that same article is reprinted in the Best of the Journal Volume 3. That article did not really have chargen much, but it only told you what initial stats Virushi characters would have. For example, STR is rolled up by 1d6+10 or something like that. It also told you what kind of careers Virushi simply would not enter into (e.g. militant careers like Marines, Army, etc)