First off, revenge porn is illegal that both Mao and Manami did. Second, Mao doesn't need to tell her shit, it's her business.
Also, if you like someone, especially if you've been friends for a long time, this is the one-way ticket to getting unfriended, hated, blocked, and possibly a restraining order.
And Haruka aiding Manami because she feels the same is just no. If you see the one you like kiss someone, well sucks to suck, you're a FRIEND. Honestly, the fact they were guilt tripping Mao like she was in the wrong was gross.