Calling that anti-reductionist is misunderstanding the issue.

> Red (or all qualia) is just the reaction of your nervous system to a stimulus.

Yes, Chalmers would call that one of the easy problems. Computers can do that - react to sensor data, which they have internal representations of - and most people don't assume they're conscious.

The hard problem is how you get from that to a conscious experience of those stimuli, which we tend to assume that computers (and LLMs?) don't have.

That's not an anti-reductionist position, it's pointing out the fundamental philosophical difficulty in making that leap from non-conscious organizations of matter to conscious ones. Even a hard-core materialist/reductionist who is honest will acknowledge that, assuming they've understood the issue.