I confess my geek-fu is not strong enough to understand what he does, can someone shed some light for the networksavvy-impared?

Well...

wget -o /dev/null -O - http://www.iana.org/assignments/ipv4-address-space/

He's asking IANA for the netblocks... (click the link to see what does get returned)

grep whois.apnic.net

administerd by APNIC (Asia-Pacific)

grep ALLOCATED

currently in use (not legacy ones)

cut -d " " -f 1

culling everything from each line except the IP/mask (the first item)

xargs

and strips the carriage returns to generate a list of IP blocks in the AP region.

# need to add in .0.0.0 though

Of course he has to manually add in the .0.0.0 for each block for the next to work

for asia in 58.0.0.0/8 59.0.0.0/8
do
$fw -A INPUT -s $asia -j DROP
done

He then sets up his firewall to instantly drop any packets coming from any of those IP blocks so he can't hear them.

It's a bit sledgehammer/nut IMO.