I found out why! I google'd and here are some of the answers I found....
From
Florida Statute 876.12:
876.12 Wearing mask, hood, or other device on public way. No person or persons over 16 years of age shall, while wearing any mask, hood, or device whereby any portion of the face is so hidden, concealed, or covered as to conceal the identity of the wearer, enter upon, or be or appear upon any lane, walk, alley, street, road, highway, or other public way in this state.
Most mask/hood laws were generally written with the intent to suppress Ku Klux Klan activity.
Texas has a similar law. It was written in the '30s or '40s to cut down on public lynchings by the KKK. Nowadays, it's usually enforced to keep college kids from getting too rambunctious on Halloween.