The US has a law called the foreign Agent Registration Act, which has been in force since 1938. The purpose is to create transparency for the US public for any individual or group that is an advocate for a foreign government or entity. If an NGO in the US were to be taking funds from the same sources as NGOs in Israel, meaning originating in EU governments, then they would have to register as foreign agents. Yet, somehow this doesn't diminish US democracy, but actually enhances it as it gives the electorate in a democratic society the right to know from whence influence is coming. The Israeli public has the same right to know, which is why as an Israeli voter I would want to know which NGOs are receiving funding from which EU governments. it is only fair.
U.S. says working on initiative to de-escalate Syria fighting, with focus on Aleppo (Reuters)
from the article: Israel joins UN list of states limiting human rights organizations