Maaaan, you're completely wrong.
Here lies document (on russian and in .pdf), in which it is written in black and white how Zagitova got into the national team and was invited to control skates of last season. The fact that I should send you on this link already shows your ignorance of the question: those who followed the figure skating in Russia at least last year, are aware of this situation. For example, you can find even in this forum a lot of posts - "who is this girl at all" "why was she invited at all" "she does not deserve this," etc., and so on.
Another inconvenient fact is RusFed every season, I emphasize,
every season does this - i.e. violates its own rules. (I wonder, is this news for you?) And what's interesting is - almost always subsequent events prove the rightness of the federation. So it was with Zagitova, so it was with Pogorilaya, it was with Plushenko, so it was with the Kovtun, so it was with Makarova, after all. And if you do not trust RusFed - trust your own eyes, your understanding of figure skating and common sense. (by the way, big bosses from the fed do exactly so). And you can also try to do so: go - and watch the video of performance of Kostornaya at Moscow Open. And try to say after that that the level of her skating (the level of skating, and not some bureaucratic rules) does not deserve participation in the JGP.
And now, when there is a choice whom to send to the JGP stage, her or, for example, Konstantinova or Vasilieva, the answer is obvious. I'll explain it especially for you: while both Konstantinova and Vasilieva are really good and promising young figure skaters, it's completely incomprehensible at the expense of what they should defeat the foreign competitors as right now, as in the future. Why should judges scoring them higher than others?
A typical mistake. Some fans believe that their favorites should win simply because "we want it so much", "it should be so", "they are simply the best" and so on. RusFed thinks another way. They are always in search of such athletes, who somehow favorably differ from others, at the expense of that they will win both right now and in the future. And if you do not see this in Alena Kostornaya - go already and see the video of her performance on YouTube.