Not sure if this really is a bug/oversight or is intentional (maybe it doesn't work while enabling NEON?), but at the top of the KODI log it says:
Not that enabling NEON in the KODI build would noticeably improve performance, wouldn't enabling it be better than not enabling it?
EDIT: Upon doing more digging, I ran across a merged PR from a month ago that kind of explains why neon is disabled. Here is a couple commented lines that were included in the change from the PR:
Code
# change this to --enable-neon when AArch64 NEON performance is improved
+ # check performance with test/benchbitslice
It seems to suggest NEON introduces a performance regression when enabled.