Just seems mor beneficial to take them out than I advertantly taking out a teammate, they could be a teammate to but as they aren't helping...
It's not really beneficial at all to lynch a low/non-poster. Well, it's perfect for scum to lynch them, but there's no benefit for town.
If they are mafia, then there's nothing to defend them with really so they won't bother. If they are town, they're pretty easy to just lynch without consequence. As they don't have many (if any) interactions with other players, you really get absolutely nothing from their flip either way. If they're mafia you can't really find their teammates, other than possibly ruling out the first person to suggest lynching that player (though someone not posting is an idea bus candidate so even that's not very strong).
The way to handle the low posters is if you have a night kill, then kill them. If you are a cop, then cop them. You could also track them. Either way you need to try and get their alignment through night roles as it's not really possible during the day, and mafia will never kill these players as they're ideal to keep around. Inactivity/apathy is mafia's greatest ally