The understanding that seems to have evolved concerning the lubricity vs journal size/rpm..is that a certain amount of minimal wear, due to the TIME that the motor spends at the higher rpm..vs the amount of time it takes for the existing lubricity to 'thin out' to the 'metal on metal' contact point...is acceptable to BMW. But is it to you, if you plan to keep the car for a very long time?
Meaning, if the motor does only spend short 'bursts', ie a second or two and fractions of seconds at these 'wear beginning to creep in' rpm levels, then..the slow but accumulating wear is 'acceptable'. Thus the higher than lubricity level rpm limit.
The problem comes from folks who don't understand what a reasonable person does (who has studied these things, or actually drives and understands the odd car), which is that the RPM limit is not something that can be engaged in a long term way. So you understand it, but some don't put in the effort.
In racing, the 1/2 to two seconds of optimum acceleration you get from either up-shifting or down-shifting at the red line, when popping into the next gear..is critical to the race, therefore the need to shift at or near redline.
As stated, the consensus is that the risk is real, and the wear is real, but the minimal wear in most real world situations with realistic people....is considered to be 'acceptable'.
This is why it is important to look at the ECU memory on the given car, as BMW bases it's warranty claims and 'goodwill' repairs based on that information.
BMW has been known to replace engines/bottoms/tops/etc for free..but only in cases where they can ascertain that flat-out abuse has been ruled out.
If you are buying an M3..and the ECU has been flashed to increase the RPM limit, or change the timing/etc..walk away.
Get a fresh lady driven one for your track car. It's an accumulated abuse and use issue. BMW will not touch a modded ECU car with a 200 foot pole.
Just my advice and experience with BMW's. Hope it helps.