Your question seems to imply that people have to be corralled towards a specific action, which to me comes across as rather cynical.

Why is it not possible to lay out your arguments honestly and let people decide on the merits?

I think, part of the issue is that, as a mass of humans, we tend to be rather dumb. And they certainly don't decide on merits, in aggregate. It is somewhat questionable if they decide on merits even as individuals ( unless we expand the definition somewhat ). But it is possible I got too cynical.