This is totally in congruence with the Olympic ideal of inclusiveness, bringing together the world's athletes instead of shutting some out for purely political reasons.
I am all for international athletic competitions and shared joy, even national prides, instead of the old primitive conflict resolution with violence and wars.
The IOC is not shutting anyone out for political reasons. Instead they are bending (if not outright disregarding) the rulebook for political reasons.
If DPRK missed the deadline but is being afforded special treatment, well that is mixing politics and sport.
I am certain they were given every opportunity to RSVP the same as every other delegation.