Question

Why did they do this ?

Iran lawmakers shout 'death to America,' burn U.S. flag after Trump nixes nuclear deal.

Answer 1

Heyaa ! Folk here's your answer

Iranian lawmakers shouted "death to America" and set fire to a paper U.S. flag during angry scenes at the country's parliament in Tehran, a day after President Trump pulled out of the nuclear deal.
The protest came as Iranian officials, including parliament speaker Ali Larijani and President Hassan Rouhani, said Wednesday they hoped European leaders will work with them to preserve the deal between Tehran and world powers — without the U.S. — but stressed that the nation could now decide to resume its nuclear program.

"If necessary, we can begin our industrial enrichment without any limitations," the Iranian leader said. "Until implementation of this decision, we will wait for some weeks and will talk with our friends and allies and other signatories of the nuclear deal, who signed it and who will remain loyal to it. Everything depends on our national interests."
Iran’s supreme leader, who has the final say on all state matters, stru.ck a more defiant tone. Ayatollah Ali Khamenei directly challenged Trump, saying "you cannot do a dam.n thing" after Trump announced he was renewing sanctions on Iran.
During the demonstration in parliament, lawmakers held up the flaming U.S. flag as their fell.ow parliamentarians joined in anti-American chants. They also burned a piece of paper representing the nuclear deal and stomped on the papers’ ashes. Larijani, according to the Iranian Students' News Agency, said Trump lacked "mental capacity."
Later Wednesday, Trump warned Iran against resuming its nuclear weapons program.
“I would advise Iran not to start their nuclear program,” Trump told reporters when asked about the potential consequences. “I would advise them very strongly. If they do there will be very severe consequence.”
European diplomats meanwhile insisted that the 2015 accord would not suddenly collapse despite the U.S.'s withdrawal. Hans Dietmar Schweisgut, the European Union’s representative to China said Wednesday during a press briefing in Beijing that the EU strongly believes "that this is an agreement which belongs to the international community. This is not an agreement that will fall apart if you just walk away."