These numbers seem pretty accurate, and I wouldn't expect that they're off by anywhere like a factor of 10.

Think about it: the number of programmers in the world is certainly not off by 10 factor - no way there are 180 million programmers in the world, only 18 of which are visible.

Similarly, there's no way that 43% of programmers in the world are Go programmers, that's again quite clearly off.

I think an estimate of 700k Go programmers makes a lot of sense, maybe with a factor of x2. I would very strongly doubt that there are more than 2 million Go programmers in the world.