I think you're missing the point. Of course it's better that cranks don't have political influence. But if by disposing of that we also dispose of the influence of good small groups it's not a good idea. We don't want to throw away the baby with the bath water. It's like saying let's abolish scientific freedom and keep only the good scientists who say good things. The cure would be worse than the disease, since by keeping bad scientists out you're also keeping new good scientists with good ideas out. In the end truth does better in a free and open debate, even if that means allowing the bad parts in as well. So too in politics. Of course, you're right that in a PR system you'll get idiot communist minorities influencing debate. But by abolishing that you also lose the libertarian minorities who can influence the debate. If I have a choice between only the status quo or status quo plus communist minority plus libertarian minority I think the latter is better.

First of all, it is perfectly within the power of those who do not get elected to publish their views, they just don't get to use other people's money to attempt to implement them.

A second point is that since at present the government monopolises certain services it is very, very important that the people in power be subject to the most severe criticism possible under such a restraint, i.e. - the district system. If this means chopping off parties with low, thinly spread amounts of votes, then so be it.

Well democracy is just another form of dictatorship, but I think you mean whether I have a preference between democracy and other forms of dictatorship.

False, there is a fundamental difference, under democracy people have a chance at elections to get rid of bad or incompetent leaders, also votes of no confidence, impeachment, free press and so on play a similar role. Democracy is properly understood as a means of criticising governments, where in dictatorships criticism is deliberately suppressed. Democracy is very imperfect, but it is an improvement on dictatorship.