I think dual nationality should only be possible by being born into it. US citizens who willfully naturalize as citizens of other countries should be forced to relinquish their US citizenship. I wish the US government would crack down on this.
Why? Give me one good reason that doesn't involve overt nationalism or jingoism.
Most people will take dual citzenship for convenience when they are living in another country but still want to retain the right to return to their country of birth.
The UK government have expressed that they wish long term residents of the UK to become citizens, so in that instance most people on this board would then have to choose if we followed your line.
Also, becoming a citizen of the UK gives people the right to vote in elections, surely that's desirable that you have a voice in the country in which you live.