Conversation so far:
Why is Sgt.
Slaughter known as the Iraqi sympathizer?
A decision was made to have Slaughter support the Iraqi cause, not for the actual political reasons, but more for the fact that Slaughter liked "brutality.
Did he wrestle with force?
CANNOTANSWER.
Did he ever serve in Iraq?
CANNOTANSWER.
Is there anything else interesting?
As 1990 ended, Slaughter began challenging for the WWF World Heavyweight Championship that had been held by The Ultimate Warrior since WrestleMania VI.
Did he ever win that Championship?
Slaughter thus became the thirteenth WWF World Heavyweight Champion and was immediately challenged by Royal Rumble winner Hulk Hogan.

Question: Why did Hulk Hogan challenge him after he won?
Self-contained rewrite: Why did Hulk Hogan challenge Sgt. Slaughter after he won the WWF World Heavyweight Championship?