It's different because you're removing all barriers to access and making it easy and convenient to stalk/dox people.
Imagine you get the urge to track someone, but in order to do that you have to spend a week writing some new software. That's a barrier. And because of it you may change your mind because it's a lot of work with little payoff.
But if that info is just one click away, it's a whole different ballgame.
> I'll think about it but I don't actually know if I really want to do that because for instance I've been banned from subreddits before but I don't want a ban from when I was 12 years old to follow me around forever
Insightful that your personal experience and impact on you personally affects your decision. I invite you to think about the impact of the products you build in your CS career by putting yourself in the shoes of other people as well.
Some products should not be built, even though it's easy to build them.
On one hand, thank you for showing us all how easy it is to make something like this. No doubt organizations with more resources already have more sophisticated systems in the same vein.
On the other hand, can we agree that this product is unethical?
In many cases, when a person uses an alt, it is a direct and strong signal that they do not wish their other posts to be associated.
So this product is circumventing the explicit will of the person, and making it available to anyone with zero effort i.e. there is no barrier to getting this info.
I met someone about 10 years ago who said they built this at a university. And their argument also was "actually this enhances privacy because it lets you know something something something". And yet their research grants were coming from one source only.
Imagine you get the urge to track someone, but in order to do that you have to spend a week writing some new software. That's a barrier. And because of it you may change your mind because it's a lot of work with little payoff.
But if that info is just one click away, it's a whole different ballgame.