when i wast typing, it fucking post my comment before i explained why, go re read my comment...
there are many reasons to why there isnt a rule , and its to protect the people who worked hard to max their race.
Call tem race whores? it's still dedication to try their best to hold a fucking race, its not an easy job, trust me, i've been trying to do it for vagalion and its a bitch when u have 5 other ppl waiting to read the "change race" text in chat, or to see u go afk or kicked etc...
but the most important reason, is gameplay, as explained above:
in no way , shape or form, should there be a rule that would explicitely take out a max race player from being possibly helpful for the team, just to please the egoistic low level who wants to level at the worst times.
it all comes down to common courtesy, just know what team u;re joining, MAKE FRIENDS for fucks sake, and u can have a max race then...