That's arguable, and as far as I know it's never been fully hashed out, which is what
@culdeus was alluding to earlier, (I think, anyway).
The "I'm just streaming it" side just says you're watching it live, and since the file lives in an ephemeral state on your device and you never really "have" it, other than when you're watching it stream via your browser.
But you have to have the file on your computer to play it. The fact that by default you aren't downloading it to a permanent state may or may not be a legal distinction. You are at least temporarily in possession of it, you have to be to have it play locally for you. The argument could certainly be made that even this transient possession is enough for infringement.
Now, I know the real tasty meat for the MPAA and TV Studio lawjerks is going after those people serving streams and those people sharing scene leaks. And I know this discussion gets even muddier if you are talking about content that is regularly broadcast OTA. But for the purposes of
- movies that are currently in theater or only on DVD or pay to stream
- PPV sporting events
- Pay-for-access original programming (Game of Thrones, etc)
and any other content that isn't normally part of NBC's Tuesday night broadcast ####fest lineup -- and you know and I know that this is a large portion of the Kodi, etc body of work -- I find the "I just looked at it but I never really had it" argument pretty disingenuous. That's not to say I'm here to cast judgement -- I'm as guilty as anyone on this front. I just don't try to delude myself about what I'm doing.