In case the opinion of a third party watching this exchange is useful, I felt that thaumasiotes's comments were reasonable and your comment above is the first to contain hostility.

Your confusion may stem from the fact that you mis-read thaumasiotes's first comment and you were on the back foot from that point forwards.

Though we see milder examples of this all the time, it's still wild to witness such an extreme case. The only way thaumasiotes's comments could be viewed as hostile is if you consider any correction to something you said to be hostile.

It appears you’re being defensive. This is the Internet. You’re an unknown person saying the opposite of the correct thing checking in on OP. Their response seems reasonable for the Internet.

The person you are replying to is not being hostile, but explaining why you are mistaken in a very polite matter.