1. Because it was MINISHA who brought out the past FIRST and even LIE behind the back about Arya that he was requesting a love angle in bigg boss, while Arya TWICE swore on his MOTHER, and I believe him due to this. No son can take jhooti kasam of his mother. Its pretty understandable.
2. Minisha lied about a few contestants also like karishma and twisted sushant's words made it GANDI GAALIYAN so she already LOST her credibility in viewers' eyes.
3. Minisha had NO answer hence she took the smart root of being silent, using gender card and had an IDIOT like Puneet to back up her sob drama.
I do nOT support Arya, but with all these open facts on the show, I think he is more reliable then Minisha Lamba.