The author holds a Finnish call sign, so it would be more appropriate the Finnish authorities (Traficom). That said, it's still a bad look on Apple's design or production engineering. I would expect a higher level of quality.
Because it probably isn’t violating the FCC limits. Looking at the chart he shows, there isn’t much power coming out.
The author’s use case is relatively niche. The FCC limits aren’t designed to be so strict that devices can’t emit measurable radiation at all because that’s an impossible task.
The only reason the author is hearing it is because he is literally tuning a highly sensitive radio to that frequency and putting it right next to the device.
There is a big possibility the author just bought a counterfeit, AFAIK all consumer electronic devices have standard EMC compliance requirements, these spikes showed should be easily observed in the 10M chambers during testing.
The issue was confirmed with two separate MagSafe chargers and three or four separate AC/DC chargers. The lab test in the post was done using laboratory DC power supply powering a DC to USB converter.
Also if the interference didn't come from the disc side of charger then the issue wouldn't be resolved with ferrite bead on that end. If the issue was on the USB connector side then the bead should be placed there.