Nah, the person you're responding to is right. What you're not considering is that even despite the fact that this isn't a job, you're still working with other people - other people who are clearly still eager to work on this. You're letting them down too, and if the only update we've gotten about this in over a year is you saying 'yeah, I don't care anymore lol', I can't imagine how they must be feeling, tbh. I'm sure they're cool with it to your face, because what can they do? But I know my ass would be chapped if the leader of a project I'd put years of work into suddenly let me know the whole thing was being scrapped because they 'didn't care about it anymore'.
Just because this is not a full-time job does not mean your actions can't be unprofessional, because professionalism exists outside of a paid career. You've made a paper trail of unreliability within your fandom work with both your coworkers and your fans. That is something that can happen despite this - and your other works - being free fanmade projects. That isn't hard to understand.
Either don't blindly expect other people's undying support even when you can't keep a project you know is going to expend a lot of time and a lot of effort going, or stop working on long-haul fandom-specific projects altogether. It's really that simple. You can't have your cake and eat it too.