You are confusing game design inspiration with code/asset reverse engineering, which are entirely different things.

Taking inspiration from other games, i.e. implementing similar gameplay loops or mechanics from other games, is completely normal within the industry. Unless copyrighted, it's not illegal. Minecraft taking from Infiniminer, or LoL taking from DotA is industry practice. Claude doesn't prohibit this.

Reverse engineering, i.e. decompiling game binaries to extract source code and copyrighted assets, then generating derivative games using said materials, is grounds for a massive copyright lawsuit. Anthropic doesn't want a part of this. That's why Anthropic is preemptively prohibiting it.