That's what I thought.
The proposition did not bar same-sex marriage, which was already illegal in the state, but it made it so that if another state allowed same-sex marriages, California would not recognize the union and the spouses would not be eligible for the rights and privileges associated with marriage.
The proposition received considerable controversy, but was eventually passed. Prop 22 received the support of 61.4% (4,618,673) of the voters while 38.6% (2,909,370) voted against the proposition.