The reason to put 0% beakers into Astro was that it's the tech Gandhi is most likely to research, speculatively speaking. So the more beakers we put into it, the cheaper it is in trade value. Furthermore, Astro is a required tech for us.
We not planning to research Democracy (or Mil Sci), so why put beakers into it? It's not a required tech for us. We can steal it if someone else researches it. And the price for stealing techs is not lowered if you have put beakers into it, so any beakers into Democracy are wasted.
We could also put beakers into Rifling, since it's also a required tech on our tech path. People seem to think Roosy is researching that next, so again, no reason to put beakers into it.
Hence, Astro.