I think you are right, however this is currently not the case and asking for the reverse is counter productive because most people will not admit this.
To make it fair, I believe everyone deserve the same equal chance to participate in this event. Also, when I spoke to support, they didn't mention that it was a bug that some people are able to upgrade to stage 7, rather they mentioned that only non-mythical were eligible for it. Clearly showing that there is a bug one way or another because I was able to use my stones to upgrade my mythical weapon to stage 6.
Also, I don't see how you make this thread anymore productive, especially by spamming your image. People understand the situation and just want equality.