Why was the black panther party considered "radical" in the civil rights era?

The  Black Panther Party was considered "radical" in the Civil Rights era because their policies of direct confrontation and Marxist economic philosophies broke from the established methods of protest.

Explanation:

The members and the followers of the Black Panther Party had their own philosophy of protest and rebellion that did not comply with the methods followed by other groups or organizations fighting for the rights of African Americans. The proposed that if the rights are not granted through the means of peaceful protests, the administration should be ready for the violent ones.