Means the rights holders can take it away from you any time
Uhm. Actually. No. Not according to Itch terms, if that it refers to the license you were talking about.
Users shall retain a license to this content even after the content is removed from the Service
What they can do, is remove it from the "the Service".
This is not about IP. This is about Itch terms and publishing here and buying things that are in the cloud.
Typically, if you buy a game on Steam, it stays bought and downloadable, even if the developer removes it for various reasons. Even if those reasons are of legal nature, like expired rights to publish. Yeah, that drm stuff also means they can take away games, but the publihser no longer selling the game on Steam is not such a reason.
The problem on Itch is, that while you still have the licence, you no longer can download the files. And this also goes for files that are removed on a whim by the developer/publisher.