I wouldn't worry about that, we have clear conditions that need to be met before we release a username [1]. It's meant to prevent name-squatting, not take usernames away from actual users. Although I do want to point out that GitHub also has this [2], it's just worded differently and doesn't outline what they consider "inactive".
[1] https://about.gitlab.com/support/#dormant-namespace-requests
[2] https://docs.github.com/en/github/site-policy/github-usernam...