Chortip,
Thank you for reaching out, and I apologize for any offense that may have been caused by the campaign in question.
Teespring is a user generated platform, and while we often see campaigns that we do not agree with or support, we try to respect the guidelines set out by the law and freedom of speech, and only remove campaigns if they contain hate speech (http://en.wikipedia.org/wiki/Hate_speech).
We do take note of all customer feedback and we're always trying to improve our policies - I will pass this on to our Approval Department to see if we can take further action.