I draw a very large distinction between prejudice and ignorance. Causing offense through ignorance ('unintentional offense') is understandable, but certainly doesn't excuse you from not having done your homework. If, on the other hand, you have actually made an effort but have still caused offense through misunderstanding or ignorance, constructive criticism is probably the best way to gain the understanding you lack. If the cause of the offense isn't obvious to you in the first place (in which case, to not remove it would make it intentional), then it will probably be difficult for you to 'consider' it, and you'll probably get it wrong regardless, so showing your work to someone with a greater understanding of the issues involved and getting constructive criticism is really the only way to proceed.