I can understand why she's annoyed about this but there's a cognitive dissonance here that a lot of online chicks seem to have. She's aware of how the internet works, she's young enough, she's seen it, but at the same time she seems to believe that it should work differently for her specifically.
Granted, I don't know what 'porn forums' she might be referring to beyond this one or where else she might have seen her stuff but just seeing what gets posted on here, her 'extremely tame/normal selfies' are a whole lot of cleavage pics or just straight up shots of her tits in a tight top. I realize that's not nudity or anything particularly spicy but it's also not really just casual selfies people post on Instagram every day.
That club cinnamon thing isn't anything particularly private or VIP and it's not like she's personally friends with everyone on there, so on some level she understands and accepts that she's sharing her pics with total strangers. She could just not do that at all. Obviously she has a need or desire to share pictures of her (covered) tits and general thirst traps with a group of fans. She's not a model, she's not a porn star or any kind of celebrity and I don't think she makes a living off of it but she still feels the need to share herself in this way with strangers.