I think there's just a bit of exaggeration of how helpful suspension is in general mountain biking (beyond the obvious exaggeration...obviously we all know suspension doesn't really make you a god). Suspension definitely makes you an overall faster rider, but not necessarily better. There's one section of a climb in particular at my local trails that's very techy with scattered bowling-ball sized (or bigger) rocks & a massive root you have to hop over at the end, & I have not been able to get it with my squishy yet, but was always able to get it on the rigid. Trying to hault-hop the front wheel & rear wheel over the rocks feels like trying to skateboard on a trampoline compared to the rigid.

Now overall, my lap times (timed myself out of curiosity) are far better on the squishy, because it absorbs vibration to reduce fatigue (less standing) & makes my bike feel like a rocket through descents. But that doesn't mean I can do anything MTB related on that bike better than on a rigid.