What Kintharia doesn't have in manpower, it makes up for in technology, supplies, and alliance. It's less of stand-alone attacker and more of a supporter, providing supplies, weaponry, vehicles, intel, etc. to allied countries.
Also, the population would clearly rise over time, as Kintharia has not been subject to any major attacks, has not participated in any major wars, and therefore would have a population of at least 3 million, if not more. Still a small military.