Earlier quoted context omitted.
It seems part of the problem is that: > You have a great passport and can come back to a country that has a wealth of opportunities that are not available in most other places and in some cases no where else. could be said about many other countries which don't tax non-residents on their financial affairs in the country in which they've chosen to live. So I think some find it hard to see how the US can justify it.
Except the passport obviously not all of it as I said. If you are paying that much tax then paying $2k to not be American isn't that high.
Now you mention it, renouncing citizenship seems relatively costly compared to e.g. the UK, though I have no idea what the average cost is for renunciation. Perhaps the UK is abnormally cheap! (EDIT: Should probably have pointed out that it's currently £144, or about $215.)
It would seem a shame if people felt they needed to renounce citizenship to avoid hassle/tax. Of course, some may argue that if they want to renounce at all, then perhaps they're not committed enough anyway, but I wouldn't argue that.