Ienatsch iirc is a former magazine test rider who got into racing and nearly won an AMA 250 championship. So he should know his stuff and he should be able to express it. But context is important and especially so here.
The top racers brake hard almost to the apex because they have top-racer skills. Even then Jorge Lorenzo, until last year the benchmark in MotoGP, was widely known to have developed unmatched mid-corner speed by getting onto - and off - the brakes sooner than his rivals.
Ienatsch in that article recommends using a wee bit of brake going in. Not a lot - he says most of the braking should happen beforehand. His point IMO is that if you are using a bit of brake then you can more easily use a bit more if required.
What he neglects to distinguish is the way racers trail brake from the way good road riders trail brake. Top racers are not holding a bit of brake just in case they got in too fast, or the turn tightens up. Either scenario will cost them half a second and the best racers' lap times vary by only a couple of tenths lap to lap, unless they are overtaking or defending a line. They know exactly how tight each turn is and if they are fine-tuning their apex speed with the brake we are talking small fractions of one mph. Ienatsch knows this and I imagine the reason he brings racing into the piece is for emphasis.
In road riding the turns usually are much less familiar and he is simply pointing out that it can be helpful to feather the brake in a turn rather than succumb to the belief that in a turn the front brake is off limits. Hence his anecdote about cruiser riders who'd never used the front brake.
But I doubt very much that the author of The Pace is proponing rushing into road turns so hard that you need
to use the brake. Think about it: if you can use the brake while leaned over, then if you weren't using the brake you could lean over more.
The deeper point here is that the road (or trail) isn't the track. Cornering on the road at track pace is a quick route to the cemetery. Typically we all have heaps of mid-corner grip to spare most of the time on the road, and especially on unfamiliar roads. Most of the time if we run wide it is not because we run out of grip, but because we can't steer the bike quickly enough to make use of the grip we have, or because the grip level is uncertain and we don't want to test it. in either case braking is a good option, since we have grip to spare - or if we don't then at least we can learn that with the brake. That I think is Ienatsch's core point. And so he recommends being prepared for that choice, by holding a wee bit of brake going in. But - critically, I think - that wee bit of brake isn't really necessary for making the turn. It is just about settling the bike. My point was that those entering road or trail turns hard-ish on the brakes could find some speed and safety by getting slowed sooner. It is not clear to me that Ienatsch would disagree. (But I've been wrong before.