And what justifies the massive land grabs governments make, claiming ownership and domain of large swathes of land unused, uncultivated, lying bare? Because they said so?
Hmmm. I'm not quite sure what you are trying to say here. If you can't vote, then sure, there's nothing you can do about it. If you think voting changes nothing, then there is no argument that will convince you and I suggest you move to a dictatorship and settle down - you obviously don't need the vote or any ability to influence the government under which you live.
In short, the land is owned by the community - not you - and the government, voted in by the community, holds it on behalf of the community. You may not like what they do with it (and sometimes I don't either) but you need to work to change their minds and support those who think similarly. If you have a political environment in which many people don't vote (USA, Britain and other such places) then sure, you've got a hard road to hoe. Nonetheless, there are so many examples of how change has been brought about by voting and political agitation, that there's no need to quote them here.
Your paternalistic liberal views can justify anything from genocide to censorship. Your argument could be used to justify Jim Crow laws in the old South.
This comment is completely and utterly contradictory. I don't know what passes for liberalism where you live, but you appear to confuse dictatorship of a party or junta with liberal values of equality, freedom of speech and other such weirdly liberal things as freedom of association, the rights of workers and the poor and so on. Liberal views have never justified anything you suggest here. Freedom from slavery was a 'liberal' 'humanist' movement which was opposed by those who opposed liberal views.