I don't remember forum being pro-Bani in season 10. It was polarizing regarding her. She did have most fans and she won every poll. But she was also bashed a lot and was considered useless by others. People called her fixed winner of that season. I'll say the daily discussions revolved around her but the forum wasn't pro-Bani.
Though people didn't care about Manveer. There wasn't even a celebration thread after his win. Forum didn't hate him, but didn't love him either.
I wasn't around during season 11 so don't know about it.
In season 12 nobody cared about any contestant which is currently also happening with season 15.
Season 13 yes the forum was against Shukla and supported Asim.
Season 14 Rubina was bashed alot and she won.
So yeah I guess you're right. Winners are never supported on this forum. But is any contestant ever massively supported on this forum?
From the time I've visited this place, the only contestant who has got overwhelming support on this forum is Asim imo. Channel's biasedness against him really brought the forum together that time.