If I received that report, my thought process would immediately be, "It seems pretty coincidental that I'm getting this report right after registration closed. I bet this report was withheld until now intentionally so that the guild would be effectively DQed from the GST."
Knowing that, I feel like it would have been a better decision to rename the guild and then punish the leader following the GST. It's held once every three months, so there could be a little consideration put towards that, along with the fact that the report timing was clearly a manipulation of the tournament.
I think a punishment was deserved if it can be proven that it was apparently a racial slur, but keeping the team out of the GST 30 minutes before was not the correct punishment. Just my two cents.