have you actually ever been to namibia?
it is a wonderful place - and i would recommend it 100% for first time africa travel
if you dont like one aspect of their society fair enough but target the specific issue.. a general boycott will hurt people who need the money and are not responsible for this and have no power to stop it

in fact here is a good web link if u want to visit namibia
http://www.wilddog-safaris.com/

i will support namibia just dont like the culling