Actually the UN tends to complain about slightly different issues rather than taxing of expatriates:

> In 2015, a 500-page UNHRC report detailed allegations of extrajudicial executions, torture, indefinitely prolonged national service and forced labour, and indicated that sexual harassment, rape and prolonged sexual servitude by state officials are also widespread.

https://en.m.wikipedia.org/wiki/Human_rights_in_Eritrea