This has the effect of making unpopular opinions invisible.
That doesn’t seem to happen in practice (yet) - downvoted posts are usually much more likely to have a tone or quality problem than be an unusual opinion.
You also aren’t addressing the fact that in practice people are more likely to (down)(up)vote things which have already been (down)(up)voted, which leads to karma sinks.
Possible, but that’s not a huge problem in itself; and the effect doesn’t seem very strong (it’s not rare to see posts eventually change sign).
That doesn’t seem to happen in practice (yet) - downvoted posts are usually much more likely to have a tone or quality problem than be an unusual opinion.
Possible, but that’s not a huge problem in itself; and the effect doesn’t seem very strong (it’s not rare to see posts eventually change sign).