I don't know about you, but I usually don't want to receive notification emails. Did you explicitly ask for it? Good. Is this some stupid notification that I won't care for and was enabled by default? Congratulations on getting flagged.
That's what 'transactional' means... it's supposed to be used for the end or beginning of a transaction (reset password, receipt for a purchase, things like that...)
Things like friend requests are also transactional email by definition. So are those "you left your cart behind, want to complete the purchase?". That doesn't mean that you asked to receive it.
Come on, sometimes it's better to be understood than to be right. Fuck the definition.