"'We Shall Overcome': Mourners Honor Orlando Victims At The White House" from http://dcist.com/2016/06/emotional_scene_outside_white_house...
"'If that young man thought he was going to divide this country he failed miserably': Thousands unite and sing We Shall Overcome at Charleston prayer vigil" from http://www.dailymail.co.uk/news/article-3132292/Thousands-ga...
"NAACP leaders joined local clergy and others to call for police reform in Chicago. After speaking with media, protesters linked arms and knelt in the street while singing "We Shall Overcome," blocking traffic." from http://abc7chicago.com/news/jason-van-dyke-posts-bond-leaves... .
"Citizens were joined by religious leaders, city leaders and a Huntington police officer and walked through the streets singing, "we shall overcome," and chanting, "stop the drugs, stop the violence."" from http://www.wsaz.com/content/news/Prayer-for-peace-vigil-held... .
There are also examples of "We Shall Overcome" being sung by politicians for something other than murder:
"House Democrats sing 'We Shall Overcome' shame GOP during sit-in" from http://www.kens5.com/news/politics/national-politics/house-d...
Is the embarrassing part in the Swedish case the it was a politician who tried to organize the singing? Or was it the implication that immigrants in Sweden are treated like black people in America? Or the expectation that immigrants would both identify with the American civil rights experience and know the song? Or something else?
If a politician in Sweden were to lead people to sing The Internationale, would that also be seen as an "empty gesture of solidarity"? (My assumption is that socialist-leaning Sweden has politicians who sing the national anthem. https://www.thelocal.se/20090406/18692 says 'the [SDU] party also offered up renditions of socialist and communist songs such as "the Internationale" and "Song for Stalin"' so it's not like it's an uncommon song there like it is in the US.)
Now put that in a totally unrelated situation, in a foreign country, and used not as a grass-roots song sung for solidarity, but as a top-down suggestion...
Context matters. The song itself isn't the issue; singing 'We shall overcome' might have been fine after a free and frank exchange of views in which the crowd had had a chance to articulate their grievances, and the politicians had had a chance to explain what they proposed to do about them, and common ground had been established.
Thank you. This is what was missing from Wikipedia and other comments.
Seems pretty obvious to me. Responding to a real political problem with an empty gesture of solidarity is everything people don't like about politicians.