Actually Tot, it rather depends on your definition of slavery.
While the word itself is taboo, effective slavery in the classical sense (unwilling service for little or no pay) is deemed to be legal by many governments worldwide. Not merely in war-torn African nations, either. For instance, in Israel, hundreds of Palestinian children are arbitrarily imprisoned in Israeli adult prisons and are used for forced labour (between beatings and interrogations) each year.
So while such atrocities are indeed against true, applicable law (international law) local governments often deem them to be perfectly acceptable. Yet another example of why international legal standards are necessary for moral governance.
Every nation in the world may declare itself to be opposed to "slavery", but it's astonishing how many practice it institutionally under different names.
[FW] Spider AL
Hewwo, meesa Jar-Jar Binks. Yeah. Excusing me, but me needs to go bust meesa head in with dissa claw-hammer, because yousa have stripped away meesa will to living.