From the second paragraph you posted, if they created a compnay that does music promotion, it seems like you could delete your files off Streem and they would no longer have the rights to do anything besides store it. In fact, storage seems to be the only right you can't revoke. Isn't this the same for a ton of other companies that allow you to upload content (i.e. doesn't Facebook get to keep your data even when you delete your account?)
ritikm gave a pretty detailed response to why they request those rights. To dismiss that explanation with "Streem is using this just to gather lots of content and sell it for profit" seems like unwarranted FUD.
Or, they could simply put in their terms their interpretation and I wouldn't have a problem. But they didn't. They selected to give themselves full control (even after deleting).
Also, you may want to read that last TOS paragraph closer, especially the part about how they aren't relinquishing control of your data or their ability to copy/distribute it. You only read the first part of it, but ignored completely "The above licenses granted by you in User Content for which the Service does not provide you a means to delete or remove are perpetual and irrevocable."
So, what that actually means is, the entire part before is moot, if Streem isn't giving you access to REMOVE stuff. Which in the previous paragraph of the TOS, they say they don't have to (and won't give you access to REMOVE data). They may let you delete it, but not remove it. Legal stuff is fun to parse and written like this so they have loopholes.
How they behave and act according to their TOS is complete speculation at this point. My concerns are that their TOS is giving them the keys to the kingdom and asking me to trust them. If they only wanted these permissions to stream it, then say that. If they want permissions to transcode it, then say that. If it is just for their use, then don't say they can give other companies access/permissions to it.
ritikm gave a pretty detailed response to why they request those rights. To dismiss that explanation with "Streem is using this just to gather lots of content and sell it for profit" seems like unwarranted FUD.