Question: When are human rights groups labeled “terrorists” and their members subject to imprisonment or worse?

Answer:  In Israel, according to Human Rights Watch, Amnesty International, the Sunrise Movement, and the Green-Rainbow Party. 

More than 280 US organizations have supported a letter, sent to Secretary of State Antony Blinken, on October 29^th.  They express solidarity with Palestinians, whose fight for liberation, it says, is linked to movements for social justice across the world: “While our government has long offered unconditional support to the Israeli government, our movements and organizations will always stand first and foremost with the rights and safety of people.”

"The six organizations targeted by Israel, which the letter describes 'as part of the bedrock of Palestinian civil society,' are Defense for Children International - Palestine, Al-Haq, Addameer, Bisan Center for Research and Development, Union of Agricultural Work Committees, and Union of Palestinian Women’s Committees." 
The Center for Constitutional Rights

These human rights organizations now face possible mass arrest and being shut down by the Israeli government, and anyone identifying with the groups can also be subject to imprisonment, according to Israel’s draconian 2016 counter-terrorism law.

Concurrently, progressive members of Congress just introduced the #StandWithThe6 resolution, H.Res. 751, to defend these six esteemed organizations, which are known for powerfully documenting Israeli human rights abuses.

Co-chairs Lois Gagnon and Rick Purcell stated on October 28, 2021, “The Green-Rainbow Party is proud to stand with our fellow human rights organizations in demanding the Biden Administration must cease its uncritical support for Israel as it violates international law.   A threat against the Palestinian human rights movement is a threat against movements for social justice everywhere”