I'm afraid you don't decide what comes across as hostile. Things can be discussed in many ways, yours is one of assuming to hold all the answers in a conversation with a stranger you know very little about. I would reconsider this. You don't know what I was buying, for what reason, or if there was a realistic alternative. You just say "you weren't born with it", and "it's the truth". An unconvincing way to argue whatever point you actually have.

If you find truthful and accurate statements of fact to be hostile, I don't know what to tell you, other than perhaps clarifying that I wasn't intending to be convincing or persuasive.

Those that care about the truth will be persuaded sufficiently by facts, and everyone outside of those that care about the truth I am not interested in spending any effort persuading.

Does that mean you do not care about the truth, as you seem unpersuaded by the fact your missives are found to be hostile?

opinions != facts

Unfortunately, being an asshole tends to outweigh being correct in conversation. Maybe work on those social skills, bud.

you're not coming across as terribly polite

Those things are not mutually exclusive? You can say to someone "I want to punch you", and that can both be the truth and hostile.

...and yes, you're being extremely hostile. There's a reason you got banned off of that other site...