English was not my first language, and this peculiar phrasing confused me. Asking for clarity seems like a natural thing to do in this situation.
This sub-thread reminds me that there are many informal rules in languages that are rarely taught, and which can trip up non-native speakers. Informal shorthands, idioms, slang, etc.
There is a rudeness in making it one of these faux-questions filled with implications instead of clearly stating what it is you want to say.
And as mentioned elsewhere, the entire thread seems like a good natured discussion: perhaps it felt different without the original "edit".
1. is sincerely asking a question
2. accidentally hit they question mark key instead of the period
3. is mimicking the valley girl inflection
It's not that much of a problem here, but it's much more pronounced in places where people rarely use complete sentences to begin with. Such as chat rooms, etc.
:-) I was thinking this but couldn't find the right phrase.
It could also be expressing uncertainty. You want to make an assertion but not 100% sure you are right. A question mark at the end expresses some self doubt and leaves it open to correction. I use '?' that way quite often.