Apple HFS+ didn't have file data checksums either. The default filesystem on most Linux distributions, ext4 doesn't, it just stores checksums of the file metadata, not the file data. Same story with Windows NTFS filesystem. Microsofts newer ReFS filesystem has file data checksums disabled by default. So it seems like a tradeoff that most of the major operating system are making. Most likely related to performance.

Edit: macOS disk images do have a checksum of the whole image data though. The issue mentioned in the article seems to be caused by an oversight in the disk image helper app, rather than in the APFS filesystem itself.