Utter nonsense. This is patently untrue. There is no such registration process in the US. NGOs in the US who file for not-for-profit status under section 501c3 of the IRS tax code are free to accept donations from charitable sources abroad - including governmental sources - and to express political opinions that include direct opposition to governmental positions.
U.S. says it killed 10 AQAP Islamist militants in four air strikes in Yemen since April 23 (Reuters)
from the article: Knesset revives attempt to restrict foreign funding of left-wing NGOs