Metal, no way. Not hate-filled enough.
Rap, forget about it. Not even close.
Hardcore, don't even get me started.
If you want real hate-filled music in its purest form, you need to explore the musical genre known as POWER ELECTRONICS.
Whitehouse are the obvious choice, and have only gotten more extreme as they've progressed. Any albums of theirs from the mid 1990s onwards are great, especially "Mummy & Daddy" and "Cruise". In fact the early stuff is great too. Also Sutcliffe Jugend have some very worthwhile tracks, you may find their album "When Pornography Is No Longer Enough" to be of interest as its particularly brutal and may be just what you're looking for. There are several other bands in this genre but those are the best and arguably most extreme examples.