I refuse to accept the view that mankind is so tragically bound to the starless midnight of racism and war that the bright daybreak of peace and brotherhood can never become a reality. - MLK
The shirtwaist factory was by todays standards a sweatshop.
It was a huge tragedy but it ultimately lead to addressing building codes in America, union rights, and women's rights.
China, Mexico, and other countries with little to no workers rights, sweatshops, and child labor need to more towards unions and worker rights.
Furthermore economic participants want to feel the price paid is a fair price, not just cheap. A lot of times I feel the junk at Wal Mart is overpriced, despite it but being very low price. Based in the quality I get, and the quantity per unit, I often feel like I should be paying a little less.
For a country that calls itself The People's Republic of Bangladesh I'm surprised they don't already have unions.
I took a lot of economic classes in college, and I wouldn't say that unions go against a free market in the academic sense. Non free markets are those controlled by the government. Governments may manage the economy by setting production levels, owning factories, or setting price floor and ceilings. A government trying to manipulate trade and imports between countries also goes against free trade.
With that being said, unions are not governments. They are workers, and as free agents in a free market, they should be able to sell their work and skills at a price they agree upon with their bosses.