The simpler objection is that smartgun technology - being a brand new thing - is likely to be expensive and complicated, which makes the guns that use it expensive and complicated. Forcing people to install it anyway is like a tax - it makes gun ownership more painful and expensive. If you care that lower-income people should be able afford guns for personal defense and that guns should be easy to use, you ought to oppose smartgun mandates as a matter of reflex. At least until the technology in question actually exists so we can see just how expensive and complicated it turns out to be, and probably well past that point.