Central government has a cancerous effect on what people expect from their government. I.E the government can afford X for X cause, far removed from basic essentials. Central government has inherent evils of injustice on localities by using the tyranny of apathy of the majority to flood out the ant holes of communities - and that is in a democracy!
And frankly, I don't want some moron sending my mates off to die, because of some tribal war in some hellhole country, as part of some 'international community" response.
The biggest threat to society is politicians with idealistic convictions of what the state should be to people, instead of politicians concentrating on equitable governance. It creates a state beholden to unwanted or onerous acts in the long term, precipitated by an electorate that doesn't want to loose it's benefits, having the end effect of strangulating the very idealistic convictions that were created in the first place.
And as OoE pointed out - why the heck would I want even more people, with vastly different principles - deciding what I can do?