I really don't understand the whole obsession over idol worship. People here take it to an extreme and seem to think it means all symbolism should be removed from Sikhi and the religion should become as austere and shallow as modern-day Islam.
Obviously, mindless idol worship is bad, everyone would agree with this (including Hindus), but its also obvious Hindu symbology had a spiritual influence on the gurus, and if you actually do naam jaap you'll find you can engage with these symbols in a way that is deeper than idol worship. Any personal practice of sikhi that doesn't even attempt to engage with this symbols, is incomplete and ahistorical in my opinion.