I'm Half agree and Half Disagree
Agree in:
All these girls , Lady Gaga, Britney, Rihanna, etc are not 100% pure dance/electronic, winner songs like: "Poker Face", "Toxic" or "Only girl "are just POP-DANCE or ELECTROPOP songs and those genres belong to the POP GENRE.
The best dance recording category should nominate and award 100% hardcore dance/electronic acts , For years this category was dominated by female pop stars divas and even Justin Timberlake while the truly dance acts were snubbed.
Disagree:
An artist can't just simply be banned from a genre category, if Rihanna or other girl decide to release a 100% dance song tomorrow with no elements of pop (just pure dance) they should be eligible for the category.
and I'm totally disagree and is unfair, this rule is only applied to certain artists. While others like Beyonce, Taylor Swift , Bon Iver, Etc can still submit songs in multiple genres , Beyonce and Taylor can submit songs from the same album to POP and ther respective genres (R&B and Country).
That is unfair.