I was going through some history threads regarding this and it was discussed that ROC would have all the designer capabilities therefore there was no need of supporting ASAP on MAC.
As on today, it is not possible to perform user management from ROC.
Is there any alternative to run ASAP on MAC?
Automation Studio is not supported on Mac.
However, I believe you can use REST API to manage user and groups on RA 6.2 or later.
Could you please check latest Release Notes?
New Features and Enhancements - CA Release Automation - 6.5 - CA Technologies Documentation
For example, you can find REST API like /users, /users/permissions, /users-groups.
REST API Reference - CA Release Automation - 6.5 - CA Technologies Documentation
I agree with you. ROC doesn't cover all functions of ASAP at this stage.
If you need the feature soon, I recommend to raise an idea and escalate it to our sales or customer success team.