There's almost no good reason to use rivnuts/nutserts for products like step sliders (and most products) IMO (this is my opinion). Sometimes you have no other good choice but for step sliders/side steps, there are better options. Hell, I'd sooner weld the things on than use nutserts/rivnuts.2nd that, why the opposition to Rivnuts?
Please elaborate. The installation of Nemesis Industries aluminum fender flares and tub (body) armor on my former 2014 JKUR required their use. Had no problems whatsoever with them. Sure, it's an extra step that requires patience/skill to get it done right, and if I didn't have to do it I wouldn't. But I also would not pass on a product I really wanted based on rvnuts alone.
Rivnuts/nutserts don't always work and they will sometimes spin around. To do right you should use a tool (yes, I know you can DIY the tool - just another reason to stay away from them).
Been there, done that. Won't do it again. IMO of course