Weaponized (teeny tiny) black holes

Larry Niven's "The Hole Man" dealt with a weaponized black hole, much as described in this article.

I also imagined this was going to be about keeping black holes just above the evaporation mass, and then starving them out before launching them at a target, so they "detonate" right as they arrive.

This seems unintuitive to me. The sun is a million miles in diameter, so surely shrinking that to zero would lower the amount of gravitational force infinitesimally since the gravity is 1/distance^2 not linear. I would think the planets would sort of drift ever so slightly farther.