They actually want to destroy it, but recognizing that they cant do that right away, they are calling for a Burka to be added. From the website Shariah 4 America:
In Islam, the public veneration of idols and statues is strictly prohibited. This has forced sincere Muslims to develop realistic plans that will aid in the removal of the Statue of Liberty.
Due to the scale of the task at hand, it is highly likely that rigorous safety checks will need to be employed before the demolition of the Statue of Liberty can commence; thus as a temporary measure, it is proposed that a large burkha is used to cover the statue, thereby shielding this horrendous eye sore from public view as well as sending a strong message to its French creators.
Post demolition, it is recommended that a minaret be built as a fitting replacement, allowing the glorification of God to be proclaimed daily as well as act as a powerful reminder of the superiority of Islam over all other ways of life.