The smartkey you buy from Lexus is not preprogrammed, essentially blank. The smartkey you bought, probably from ebay, is programmed for another car. Unfortunately you can not reprogram that preprogrammed smartkey. We see this quite a few times, people go on ebay buying the smartkeys to save some money only to end up paying more in the end. Now since they don't tell us they're buying preprogrammed keys, we attempt to program the smartkey only to have it fail, and we've done quite a few of them.
So when they tell you they can't, they're saying they are saying unable, not unwilling. Don't spread your misinterpretation of the facts.