I agree that jwr1 comes across as a bit passive aggressive here, but you're the one that started it. If you're wondering why, take another look at what you wrote:

You shouldn't have made kbin.earth the default instance when signing up from the Interstellar app if your instance has some serious security issues! I need answers NOW!

No comment from the admin of kbin.earth even after 13 hours of posting! This doesn't inspire much confidence in you or your instance or your app

This is definitely really rude. Your comment here is also significantly ruder and way more aggressive than jwr1's was.

Judging by what jwr1 said, this seems to be a rare issue with Mbin itself, likely caused by something on your end. It has nothing to do with kbin.earth specifically, or at least that's what it looks like. That's probably why jwr1 is taking it more lightly and not as seriously as you are. kbin.earth just runs the latest Mbin code after all, and jwr1 isn't an Mbin dev themselves — they just use the API. So while they're willing to help, this isn't really their problem directly. You should be bringing it up with the Mbin devs instead.

On a side note, are you seriously upvoting and boosting your own content...?

If you're doing the upvoting because Lemmy users start at 1 upvote: don't. The initial Lemmy self-upvote is a lie, or at least was when I last checked. It's there to discourage users from upvoting their own posts, and it's only cosmetic. There's no initial self-upvote behnd the scenes, at least as seen from the federated side. Newly created posts and comments federate with 0 upvotes from Lemmy instances.

No good faith idea why you'd boost your own content though.