There is absolutely no doubt that some people find learning to spell much easier than others. Just as some people find Maths, Music, tying their shoelaces and every other human activity easier than others do.
But that is a very long way from saying that some people can't learn to spell and that the lucky ones just have a "gift" for it which has been denied to the others.
Too many people believe in the Theory of Talents. We think we are born good at one thing or another and no good at other things. Then we think, "It's not my fault that I'm so bad at it. I haven't got the gift." That wouldn't matter so much if it didn't make us go on and say, "And there's no point in my working at it, because, however hard I tried, I wouldn't be able to do it." Of course, if you really do believe you never will be able to do something, you would be very foolish to go on trying. But the Theory of Talents is wrong and trying brings amazing results.
The sober truth is that we certainly are born with different aptitudes. but that just means we have to work harder at the ones that don't come easily. I don't mean that everyone can be a great writer, but everyone can learn to write well enough for their own needs. Often it takes a long time before we realise what a nuisance it will be if we can't get things down on paper. A lot of people get a nasty shock when they find they do need to write after all. It is a pity that we don't all find this out at Primary School, but even when you are grown up it is not too late. There is a clear, effective way of improving your spelling described in Learning Individual Words and First Things First: How to Get Started.