Hi,
I have just the same issue: how to exclude some rules from the quality profile.
But the solution above doesn’t work anymore. “Copy” works just in the same way as “Extend”. So it’s not allowed to deactivate rules in the newly created profile. Deactivate button is greyed with the message in the pop-up “This rule is inherited and can not be deactivated.”
Can you share some screenshots? Are you sure you aren’t copying a profile that has been extended from another profile? I’ve tried to make it clear below.