Supposing for the sake of argument that the Illuminati were real and you were in charge of it. You know a bunch of weirdos on youtube know the truth and are generally regarded as cranks. Would you bother concerning yourself with them, or would you ignore them since they're pathetic and powerless? I'd ignore them.
To be clear, I don't think the Illuminati are real, but I don't think your reasoning is sound either.
An all-encompassing conspiracy orchestrating events across the globe, sparing no effort or expense to weave us all into an inescable spider's web of connected threads, that then says "eh, probably nobody is even going to listen to those guys, let's not bother with having the intern fire off a few boilerplate take-downs"?
Sure, why not? It's obvious "probably nobody is even going to listen to those guys" is true...
Why not? Because what evil puppet-master settles for "probably ok" when a slight extra effort buys certainty.
One that isn't totally neurotic, presumably. Just to reiterate, I don't believe such an organization exists. But when trying to understand the plausible actions of even fictional characters or organizations, I try to imagine myself in their shoes. If I were in their fictional shoes, I would ignore the people who say I rule the world if those people are widely mocked and derided as insane by the general public. To do anything other than ignore them would be to risk giving them a sliver of credibility.
Of course if one tries pointing this out the response is sometimes "oh, they're so powerful that they like to mock us", but more commonly just to accuse you of being a shill/deep-state-agent/whatever.