I don't know if I fully concede that, but it's almost immaterial, because the company ripped it off the platform and rehosted it on their own site.
> the article mentions they did ask for permission before doing that
No. "Crocs pulled the photo and posted it to their website [...] It was only much later that Crocs sought explicit permission from Ms. Way, which she declined." From the NYT source article: "The company had not asked Ms. Way for permission, and she was not aware that Crocs had used the photo until a reporter contacted her on Instagram."
You're appealing to what is "reasonable" to expect or not expect someone to do with your content, but it doesn't really matter -- reproducing someone else's copyrightable work without their express permission is illegal, and hashtags aren't express enough. (In the US at least, and again I'm not a lawyer.)