In a departure from previous years, the New York-based watchdog's annual report did not open with the latest news from active war zones, but instead focused on the knock-on effects of conflict.
"Fears of terror attacks and of the potential impact of refugee influx led to a visible scaling back of rights in Europe and other regions," HRW Director Kenneth Roth warned, introducing the report.
"In Europe and the United States, a polarising us-versus-them rhetoric has moved from the political fringe to the mainstream," he wrote.
"Blatant Islamophobia and shameless demonising of refugees have become the currency of an increasingly assertive politics of intolerance."
Speaking at a news conference in Istanbul to present the report, Roth also denounced as "despicable" legislation agreed by Denmark to seize the valuables of migrants to pay for their stay.
The plan appears "purely vindicative and purely an effort to send a signal 'don't you dare come to Denmark if you're an asylum seeker who has arrived to European Union'," he said.
The report also cites the example of France, where -- in the aftermath of the November 13 attacks on bars, a concert hall and a sports stadium in Paris -- authorities have tightened emergency laws.
Suspected radicals have been confined to house arrest without trial, and police have been given stronger powers to search addresses without a judicial warrant.
In its report, HRW warned that these "potentially indiscriminate policing techniques" risk exposing blameless young Muslim men to racial profiling.
The crackdown in Europe has been mirrored in the United States by heightened campaign rhetoric from figures such as Donald Trump, the Republican White House hopeful who has proposed banning Muslims from entering America.
Better refugee resettlement
Scapegoating Muslims and refugees, the report argues, "hurts and alienates populations crucial to counterterrorism efforts."
In addition to jihadist attacks, Europe has faced the challenge of a stream of Muslim refugees fleeing conflict or persecution in the Middle East and north Africa.
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This has stirred anti-immigration sentiment and fear of crime among the European population, particularly in the wake of reported New Year sex attacks by immigrant gangs in Germany.
But, according to HRW, the right response to such inflows is not more repressive border and immigration enforcement, but a better controlled program of refugee resettlement.
"The effect of European policy so far has been to leave refugees with little choice but to risk their lives at sea for a chance at asylum," Roth wrote.
"A safer and more humane alternative would be for the EU to increase refugee resettlement and humanitarian visas from places of first refuge such as Lebanon or Pakistan."
The group saluted newly-elected Canadian Prime Minister Justin Trudeau's decision to welcome 25,000 Syrian refugees -- some 10,000 have already arrived.
But the report urged the United States -- where President Barack Obama has promised places for 10,000 Syrians but officials are slow in processing applications -- and other richer Western and Gulf Arab countries to pull their weight.
'Dark times for Turkey'
And, while a retreat in human rights has been visible in democratic countries, it has been matched by another turn of the ratchet under more authoritarian regimes.
The environment for human rights in Turkey "deteriorated in 2015" with the breakdown of the Kurdish peace process and a crackdown on opponents of the ruling party of President Recep Tayyip Erdogan, the report said.
"Turkey basically is dismantling and eroding its democratic framework," HRW's Turkey representative, Emma Sinclair-Webb, told the news conference in Istanbul.
"This spells for Turkey dark times ahead; it spells for the region dark times ahead if Turkey ceases to become a country that in any way respects human rights."
In Russia and China, the human rights situation is worse that it has been in any period since the end of the Cold War, the group added.
"The Kremlin has been crushing Russian civil society, one of the most important elements to have emerged from the demise of Soviet rule," the report says.
"The new, poisonous atmosphere helped the Kremlin to divert attention as Russia's economic woes deepened."