Was the desire to kill Jews a primary cause of WWII?The Nazi Party had an obvious goal to commit extensive murders against the Jewish population...

No, the primary cause of WWII's Allied response to
Hitler's Germany was the other countries concerns about their borders and sovereignty.
The aftermath of the First World War had not left Europe as an entirely stable
region.

Although there were humanitarian concerns in WWII,
they were not enough to cause the Allied nations to directly confront the Axis. In fact,
the practice of appeasement, or letting Germany take over small
neighboring countries, was used until it became clear that Hitler would not, in fact, be
appeased by these smaller gains. See attached article.