Looking into their blog again just to be sure, it appears they think a return to, I guess medieval/bronze-age technology is ideal? Based on this quote:

Where might one look for meaning? The guideline is simple. If it requires non-renewable materials, modern forms of energy (fossil fuels, nuclear, electricity from any source), industrial processes, or purchase with money, then it’s probably best to treat it as being devoid of meaning.

I assume they would consider a steam engine as falling under industrial processes.