The group raises money for US sharp-shooters in Iraq and Afghanistan.
Students were selling bracelets bearing the motto: "1 Shot 1 Kill No Remorse I Decide".
"Clearly the rhetoric of that organisation raised some questions and we had some strong objections as a Jesuit university," Marquette University school spokeswoman Brigid O'Brien said on Thursday.
The students, representing a group called College Republicans, originally got permission to set up a table at the student union to raise money for US troops in Iraq.
But they chose to promote a group called Adopt a Sniper, which says on its website it supports snipers deployed by the United States armed forces in Iraq and Afghanistan. The group says it "helps real snipers get the real gear they need to help keep us safe".
The brainchild of a Texas police SWAT officer Adopt a Sniper (www.adoptasniper.org) has raised thousands of dollars in cash and gear to supplement the kit of sharp shooters in US combat platoons.
Among products sold on the site is a $15 coin with the imprinted phrase "Assistance From A Distance".