The consensus seems to be these two simple reasons:
1. Angie Harmon/the powers that be are playing Rizzoli like she is a “skinny greaseball dyke detective”. She’s so gay it hurts. Softball, field hockey, not needing a man in her life, belt buckle, gay lean, dyketastic outfits and THAT VOICE... The list goes on and on.
2. Despite no outwardly cliche gay tendencies, Sasha Alexander is bringing the gay in her own special way. Her Maura Isles is a scientific genius, but socially awkward and obviously sees Rizzoli as someone with genuine people-skills. She aspires to this; looking up to her friend. Hilariously, on screen, this fascination with Rizzoli plays out like infatuation, all longing looks and secret smiles. In short, ho to the yay.
Or as jetgirl78 aptly put it, it’s gay no matter how you slice that gay cake.
Let’s just hope TPTB never realise the femslash behemoth they have created.
This show is also deeply responsible for my (and every other red-blooded lady lover, I’m sure) rekindled ob-sesh-yone with Angie Harmon, and one Sasha Alexander. It took me so long to get over Sasha after Kate Todd’s death in NCIS. But it’s weird; she’s so very not "Kate" here. I had no idea she had this cute quirkiness in her!