Which is why before making such broad statements they should check on the other platforms, which have much less broken file systems.
(Check Ext4, ZFS, UFS2, HPFS+ and APFS at least.)
What they did is check an untuned Ext4, UBIFS, HPFS+ and NTFS vs a tuned database in a single thread scenario. Especially misleading in the mmap case where synchronization would just kill the performance dead.
I find that comparison justified: How many people are even aware of the fact that filesystems can be tuned (except for, maybe, noatime and discard for SSDs)?
What they did is check an untuned Ext4, UBIFS, HPFS+ and NTFS vs a tuned database in a single thread scenario. Especially misleading in the mmap case where synchronization would just kill the performance dead.