You're saying that the Stratton v. Prodigy case is irrelevant to Reddit when the only thing making the connection to Reddit being liable for all content on the site is a stuffty picture from 8chan citing that case? So if not Stratton v. Prodigy what case law says this?
I don't know what the law itself is, but it's common sense that wherever the content originates form, the originator is liable for said content, and in this case it's Reddit, and because we don't know the extent of the amount of posts they've edited, they're (for the time being) liable for every post on the website, of course they haven't edited every post on the website, but given the amount is unknown, then all posts are technically Reddit's until it's proven not to be Reddit's.
So since several comments were changed all content is from the provider?  This raises doubt over the use of reddit comments as evidence which should have already been questionable evidence without more circumstantial evidence to connect them.
Yes, until proven that all content has not originated from the provider, that's how this goes.
and why would the Reddit comments already have been questionable evidence, we didn't know about this occurring until recently, so that's irrelevant.
and don't know what you mean by "circumstantial evidence" when u/spez admitted to editing the posts himself in the thread where it happened.
Just because a court case predates something doesn't mean it doesn't set a precedent for the law. Where is the idea that they are automatically liable for any and every single post coming from exactly?  
Because of the implications of them editing users posts in secret, given that they've done it in secret, we don't know how many posts they've edited, and therefore you must treat every single post as Reddit's until it's proven not to be.
Prodigy hosted their own content and had software in place that would automatically filter out obscene language. That seems more than similar enough to be used as an argument in court.  It could always swing the other way, I don't see it going very far though.
That's a completely different subject now, and an easily solvable one at that, you'd examine the code behind the software, and see what words trigger the software to filter out said trigger words, easy as that, that's not editing users comments completely, that's a filter for obscene language.
Are you talking about different statutes or case law than us cause you're making an awful lot of statements as if they're fact without referencing anything..
I'm not referring to any case law specifically, but if this was something brought to the court they'd be saying the exact same thing I'm saying now, which is that given Reddit edit's users posts completely in secret without the users knowledge, and have done this multiple times to an unknown degree, we must treat every post on Reddit as their own considering there is no defined set amount of posts they have edited.
now no stuff they haven't edited every single post on the website, but that's how you have to treat this ordeal, because 
no one besides Reddit knows how many posts they've edited, so until Reddit comes out with a set number (if said number is even the true number), we must treat every post on Reddit in this way.