When dorgon issued the queue edict, what did he think forcing chinese men to adopt the queue would show?

Adopting the queue would show that they were completely supportive of the emperor.

When the new emperor of Manchu came, it was declared that all those who didn't cut their hair in a queue would get charged with treason and executed, so although many rebelled and were brutally punished, the majority of people chose to wear the haircut. Women didn't have to change their haircuts according to this law.