For example, I'm in theory opposed to the prohibition on crack cocaine, despite its strong consistent effect on personal agency, because of two things: basic moral principles (my body my choice), and the massive (hopefully unintended) side effects of prohibition. Namely, mass incarceration, black markets, decreased drug quality, gang violence, exhaustion of policing resources, the public perception of systemic racism, and tax losses. My guess is the downsides of a hypothetical ban on algorithmically optimized advertisements would be of a very different kind but similar quantity. And again, the other issue is basic moral principles. I'm not comfortable with bracketing free expression with numerous exceptions, rate-limits, inspectors, or whatever apparatchiks would be employed to enforce such a restriction.