It is not true that because you left any specific team that you are a part of, that you’d lose your access to other teams.
Think of it a bit like Facebook. You have a central user “account” and then “join” various groups with that account. Leaving any individual group does not impact the other groups.
The key here is that your core account is something *you* own and manage, but your access to any particular team/group is something that team’s admin manages.