There's so much low-quality content on the internet now - and it gets even worse in comment sections - that the only way you'll be able to detect if something is AI written if it's actually higher quality, or coherent.
True. That also requires a good portion of critical thinking and education in general, which is, let's be honest, rather rare in most comment sections. I fear that in the future we'll look at today's YouTube comment sections thinking these were the good old days ...