What it means is that insurgents knew better than to target NATO troops, just as drug cartels know better than to targets DEA agents.
NATO troops were extremely prized targets. Casualties were low 'cause they rarely got out of their bases. Warlords and foreign govts even offered bounties.
The Baltics have 6 million people. To control an insurgency, you need 20 soldiers for every 1000 residents at the absolute minimum. That's 120k troops.