It’s complicated. Other legal issues aside, it’s fairly common for large corporations to use lawsuits or the threat of lawsuits that small creators can’t afford to fight to shut down things that are legal. Even if the creator wins, that’s months of stress and thousands of dollars of lawyer’s fees, minimum. The creator of TTS figured it wasn’t worth the risk considering GWs litigious nature (including constant attempts to sue or shut down other franchises who use the term ‘Space Marine’) and moved on.