OK, you clearly define voting as being inherently violent

I didn't define voting as inherently violent.

If the whole act was simply to free the slaves and nothing else (such a proposition never happens in real government measures, as someone also stands to gain politically, and someone to lose), then yes, I would vote for it. The scenario is unrealistic, but sure.

And also, would you prefer to see that (physical rebellion resulting in mass loss of life), rather than someone using a political platform to peacefully spread the message of freedom?

There are over 260 million corpses piled up behind your "peaceful" politics in the last century alone. Government does not dissolve itself through its own mechanisms. This is common sense.

What the masses read or don't read doesn't change what is right and wrong.