Is illegal in most democratic countries... Because it subverts the democratic choice of voting citizens. If these organization reflected the will of Israeli citizens, they would have more than enough funding from Israelis. But because they don't, they seek foreign funding to help over-inflate the little support that they have. It is a clear distortion of democracy.
Netanyahu: Most of Americans see eye to eye with Israel on dangers of Iran deal (Haaretz)
from the article: In Numbers / Breakdown of foreign funds for Israeli human rights groups