I can understand being hurt by a stranger saying "it's gonna be OK." It's definitely a bit patronizing. It's never a good idea to publicly call out low-wage workers, though.
This is what I mean when saying calling for accountability requires understanding what actually constitutes as harm. It'd be one thing if she
actually lashed out at a random person she doesn't know - that would be abusive. But her post is about feelings she held in from saying to the worker.
It'd also be another thing if she exhibited harmful views, but highlighting the income of fast food workers is a bit nonsensical when nothing she complained about related to the person's labor. She didn't comment on the service or food.
Her venting starts and stops at the view that unsolicited attempts to paint her as a victim are negative and ill-intended. Sure, it's fine to find this behavior negative or overbearing, and most people finding the situation sad do just want best for her, but you can't actually hold someone 'accountable' for being (in their mind, justifiably) miserable. It's why most comments about her social media posts laser in on how they "look" or the impression they "give off" because it's hard to actually articulate any tangible harm she's allegedly doing to anyone by simply deciding to live her life feeling the world is hostile to her.
One has the right to be a fan and not feel required to closely monitor said behavior if they find it toxic, but it also feels like people who never liked Britney will disingenuously weaponize her mental health to allege harm that isn't actualized. Being miserable is not the same as doing harm to others.