You're missing the part where this would displace fossil fuels with "electrofuels", meaning for every ton of this stuff made, that's more fossil fuels left in the ground. Replacing a fossil fuel with a carbon neutral fuel means a reduction in net carbon emissions.
The other part you're missing is that this decouples fuel production from locations with large fossil fuel sources (often run by governments with authoritarian rulers who use their exports as leverage). This means that you can spread production to anywhere the sun shines which means highly decentralized, local production of electrofuels.
The third part you're missing is how this increases demand for solar panels and carbon sequestration technology which has an amazing feedback loop that makes these cheaper and more efficient over the decades, meaning that as hydrocarbon demand declines over time as other technologies take over (e.g., electric cars reducing demand from the transportation sector), this built up intellectual capital and infrastructure can be used to just sequester carbon for long-term storage, which would be net negative instead of just carbon neutral.
There's probably more you're missing but I'd just recommend reading more of the blog where he explains everything.
