Unrealistic Future?

I recently read a review on one of my books in the Beyond Earth series. I take all reviews serious. Any tips I get I try to address in the next book or use the critique to become a better author. The compliments always make me smile. Some with stories of how it helped their lives.
This particular reviewer said it was unrealistic to have a planet have so few people on it. I challenge that with: why? 

Let's go over some points in the series:

1. In book two, I wrote how the government on Earth worried about overcrowding and released a sterility spray in some public areas. 
2. In book one, I wrote that Earth was almost completely destroyed by the year 2507.  Earth wasn’t safe to live on anymore. Billions of people on Earth died. 
3. By the year 2800 only about 100,000 people lived on Earth. Half those people stayed on Earth to try and fix things. Half went to space.
4. Let's say there were 50 ships that launched into space. Those fifty ships might have carried 1,000 people each on them. Again, that’s 50,000 people. 
5. Now, fast forward a few hundred years. Let’s say for fun sake that the number of people doubled, so now there are 100,000 humans. There are thousands, maybe millions of planets and moons in the universe that could be hospitable. 
6. The ship, Valinor, landed on a planet which took on its name. The 1,000 people on that ship became the people of Valinor. 
7. Valinor is a small Earth-like planet that Valinor has 3 continents, 2 of which are uninhabited (so far). Years later, there’s about 3,000 people on Valinor. It’s a peaceful planet, not as big as Earth, but big enough. They have a small army because originally they are not in a war and the way they protect their planet is by technology…mostly done from computers and a command center.
8. In book two Akacia sends 20 people in her military to Terronda to help. That wasn't all of her military/army. 
9. They have more people who come and help them. The Splicer families, a few of Terronda's army, people in the universe who hate Caspar. Plus they have Tegar and his ship/crew helping to protect Valinor.
10. In Googling, I seem to find that 0.4% of the American population are active in the military and 7.3% of all living Americans have served in the military at some point.
11. Let's compare that to Valinor's military. Let's go with the first statistic and let's even round it up to 1%. What is 1% of 3,000? 30. If there are approximately 100 people of Valinor in their military, that's more than 3% active military. More than the United States of America.
12. Earth's population (as of January 2018) was 7.6 billion people. In the past 75 years, it has grown 1-2% per year. Applied to the people who left Earth (50,000) this would be 500-1,000 per year. It's been just over 200 years since Akacia was born, that means the population of the universe (not including aliens) would be approximately 150,000-350,000. Seems like a lot of people, but spread over the planets, moons, and space stations, the population of Valinor seems pretty average. 
13. Let's take #12 and apply it to Valinor. The ship, Valinor, had about 1,000 people to begin with. With a 1% increase in population every year for 200 years, that brings the total to 3,000. That's just births. There would have been deaths and some people who weren't on the ship were granted permission to live on the planet, so it would roughly still be about 3,000. 

As you can see, it is very plausible and believable to have these numbers. If all 3,000 people were to spread around Valinor, well, there wouldn't be a community would there? Eventually I could see expanding. Maybe allowing some other alien races to settle down? You never know. For now, it's a possible and believable future.