They're "technically" correct. That's what Torvalds initially created it as. But what it initially was, and now is are very different things. I'm sure they would call OSX a BSD replacement and not a Windows replacement. Despite many people replacing windows with it. It's pedantically obtuse.

Right now the biggest wall from wider consumer adoption of Linux. Is honestly, simply the lack of systems offered to consumers with it. Outside of a few games with kernel level anti cheat. Or highly proprietary specialized softwares. There's very little that you cannot currently do on Linux that you can do on Windows.

Your Average user/consumer doesn't install any operating system. Whether it is Windows Linux or Mac OS. They simply run what the computer came with. And that's always been windows unless it is an Apple computer. That's part of what the 1999 antitrust suit would have sought to remedy. Microsoft punished any company that had dared to even offer systems with Linux for a long time. And nothing was ever really done to stop it.