Firstly, another name for horns is the shofar in hebrew ... it's used as an instrument to warn people about the enamy ... also used as a instrument to declare the glory of the King. In mordern terms, it's used to praise God or Share the Gospel. The Satanists borrowed it from us!! Horn also represents a RAM which Abraham proved his faith and loyalty to God.
Secondly, the Six sided star (hexagram) is actually the star of David. Its used to give hope to the people of Israel, symbolise God's rule over the world in 6 direction. Again ... the satanists borrowed it for thier inverted version.
Thirdly, Pentagrams represent many many things .... Vitruvian man from leonardo da vincci means symmertry of four limbs and head .... it also means five elements .... also represents stars and planetary positions. Hence it is not nessasary satanic .... depends on how you use it.
Hence not everything with such symbolism is satanic .... but the church still consists of humans ... and humans are judgemental and always Jumps whenever they see something .... hence back to music .... if you want to play christian metal, just play .... church people are not the ultimate dictator. Sometimes, they know not what they say .... if you can find a group of like minded Christians ... isn't that a church by itself?