Why Andrew Jackson is the top
"Perhaps the most controversial aspect of Jackson's presidency was his policy regarding American Indians, which involved the ethnic cleansing of several Indian tribes. Jackson was a leading advocate of a policy known as Indian removal. Jackson had been negotiating treaties and removal policies with Indian leaders for years before his election as president. Many tribes and portions of tribes had been removed to Arkansas Territory and further west of the Mississippi River without the suffering and tragedies of what later became known as the Trail of Tears. Further, many white Americans advocated total extermination of the "savages," particularly those who had experienced frontier wars. Jackson's support of removal policies can be best understood by examination of those prior cases he had personally negotiated, rather than those in post-presidential years. Nevertheless, Jackson is often held responsible for all that took place in the 1830s."
http://en.wikipedia.org/wiki/Andrew_Jackson#Indian_removal
read this part carefully "ethnic cleansing of several Indian tribes" This wasnt part of a war, we weren't attacked, it was to free up land. That seems pretty cruel to me.
Polk wasnt mentioned on the poll be he has to be up there
"After the Texas annexation, Polk turned his attention to California, hoping to acquire the territory from Mexico before any European nation did so. The main interest was San Francisco Bay as an access point for trade with Asia. In 1845, he sent diplomat John Slidell to Mexico to purchase California and New Mexico for $24–30 million. Slidell's arrival caused political turmoil in Mexico after word leaked out that he was there to purchase additional territory and not to offer compensation for the loss of Texas. The Mexicans refused to receive Slidell, citing a technical problem with his credentials. In January 1846, to increase pressure on Mexico to negotiate, Polk sent troops under General Zachary Taylor into the area between the Nueces River and the Rio Grande—territory that was claimed by both the U.S. and Mexico.
Slidell returned to Washington in May 1846, having been rebuffed by the Mexican government. Polk regarded this treatment of his diplomat as an insult and an "ample cause of war", and he prepared to ask Congress for a declaration of war. Meanwhile Taylor crossed the Rio Grande River and briefly occupied Matamoros, Tamaulipas. Taylor continued to blockade ships from entering the port of Matamoros. Mere days before Polk intended to make his request to Congress, he received word that Mexican forces had crossed the Rio Grande area and killed eleven American soldiers. Polk then made this the casus belli, and in a message to Congress on May 11, 1846, he stated that Mexico had "invaded our territory and shed American blood upon the American soil.""
http://en.wikipedia.org/wiki/James_K._Polk
So he wanted land from Mexico and they wouldn't sell it to him, so he marched a bunch of troops into disputed territory and instigated the Mexican American war to get what he wanted.
The worst thing I can think of for FDR was the internment camps for the Japanese.
"order 9066 authorized the Secretary of War and U.S. armed forces commanders to declare areas of the United States as military areas "from which any or all persons may be excluded," although it did not name any nationality or ethnic group. It was eventually applied to one-third of the land area of the U.S. (mostly in the West) and was used against those with "Foreign Enemy Ancestry" — Japanese.
The order has led to the internment of Japanese Americans or AJAs (Americans of Japanese Ancestry); some 120,000 ethnic Japanese people were held in internment camps for the duration of the war. Of the Japanese interned, 62% were Nisei (American-born, second-generation Japanese American and therefore American citizens) or Sansei (third-generation Japanese American, also American citizens) and the rest were Issei (Japanese immigrants and resident aliens, first-generation Japanese American)."
http://en.wikipedia.org/wiki/Executive_Order_9066
so yeah 120,000 people got locked up because of their race, most of these people were U.S citizens born and raised here.