On the one hand, allowing Emil and Artem back into the World Championships would generate a lot of interest. Whether they are real contenders or not.
On the other hand, in the current political climate, bringing the Russians "back into the fold" could generate some less than positive publicity inside and even outside the sport. Imagine the coverage if one of them won it?
Either way, it's all publicity. And as Barnum (and others) said, "There’s no such thing as bad publicity".
And as speedway fans, surely we want two of the best in the series?