Netflix Omits Controversial Episode from MTV's 'The Challenge'

Netflix left a controversial episode from one of MTV's most popular shows on the cutting room floor ... an episode infamous for some severe bullying.

Here's the deal ... the streaming giant just added 2 seasons of MTV's 'Real World/Road Rules Challenge,' but fans will instantly notice something's missing ... some behind-the-scenes clips featuring 3 female cast members going after another female contestant.

The episode was titled "To Hell and Back: Hot Gossip From The Inferno 2" ... and the troubling scene showed Veronica, Rachel and Tina ganging up on Tonya Cooley by snapping nude photos of her while she was sleeping.

They later showed those pics to other houseguests. That episode was the…