At what level of accuracy is it acceptable? Cable outlets allow for a fairly targeted ad campaign (limited to one town, for example). Granted, perhaps not as well targeted as Facebook, Google, etc. But we should give a good justification of where we want to draw the line. It sounds like Facebook is getting criticism for merely being more efficient than traditional media.
As if we're saying "Yeah, we can tolerate the concept of ads, as long as they're fairly inefficient".
Ultimately, your comment sounds like the issue isn't about elections, but the dangers of extremely effective ad distribution networks (Google, Facebook, etc). As a tool, it can be used for all sorts of mass influence leading to outcomes some people do not like - that are not inherently tied to elections. Examples could be effective ads targeting a particular racial demographic regarding education. I don't see that being any more or less desirable than using it to affect an election.
I'm all for that conversation, as long as it is about the broader topic and not tied to the much narrower topic of influencing elections.