UFC fighter Felice Herrig is taking the high road in her now infamous fight with Justine Kish -- saying she refuses to "talk s**t" about her opponent ... despite what happened in the Octagon. 

Herrig tells TMZ Sports she actually really likes Kish a lot and feels bad that she's blowing up in the media because of Sunday night's poo incident on live TV. 

She actually calls for MMA fans to lay off Kish -- saying she's a really cool girl who doesn't deserve to be dragged through the mud. 

The good news for Herrig ... she's already focused on her next fight and says she wants to avenge the only UFC loss on her record to one of the biggest stars in the sport.