AFK has never been the issue.
The issue has always been the fact that the unlimited safety comes for an effectively unlimited time at no real cost.
The nature of cloaking mitigates the potential costs of it to the point that it’s not an issue, yet imposes significant costs on those being hunted regardless of any other actions the cloaker takes.
That is what makes it an “I Win” button. You cost your enemy significantly while suffering nothing yourself. There is absolutely nothing that can be done about that even if he never uncloaks or causes any further losses through direct combat. The Opportunity Cost argument is a joke in poor taste.
No, cloaks aren’t WTFOM mobiles, but they don’t have to be. Their power lies in other areas and is absolute.