Top tip for everyone who can't pierce the wall of noise metal seems to throw at the listener: Most people are really hardwired to listen to the vocals and take the rest as "background". Try to get away from this. Most Metal bands treat their vocals as another instrument among many, so they are weirdly embedded into the band which clashes with most other genres. To ignore the vocals a bit more: Try to listen to the drums. When you managed that (takes just a few seconds usually), try the lead guitar (or the rhythm if you're feeling groovy). I won't claim that you'll suddenly have an epiphany and love metal (or that you even should strive to love metal if you don't want to, tastes exist for a reason!), yet you might be able to finally get why people like this noise that insulted your ears for so long ;)