Why can't a WireGuard interface route packets to itself?

[logothesia <logothesia%disroot.org@localhost>]

Hi folks,

I have a very simple WG network with only two machines: 10.0.0.1 (NetBSD), and
10.0.0.2 (linux). Indeed they can ping each other just fine, but attempting to
ping 10.0.0.1 from itself yields the following error:

% ping 10.0.0.1
PING 10.0.0.1 (10.0.0.1): 56 data bytes
ping: sendto: No route to host
...

Is this intended behavior? If so, it seems very strange to me. Here is my
routing table:

% netstat -rn
Internet:
Destination        Gateway            Flags    Refs      Use    Mtu Interface
...
10/8               10.0.0.1           U           -        -      -  wg0
10.0.0.1           wg0                UHl         -        -      -  wg0
...

Looks fine, no?

I messed around with if_wg.c a bit, but nothing immediately caught my eye. Some
hints, perhaps?

I'm on -current 10.99.6.

Cheers,
logothesia