You're learning :). The guy isn't an expert, this is just another rotation business like Lenny at INKW with water. Ride the momentum and profit my friend.
Most pyrolysis based systems prefer only a couple types of plastics for conversion. You need a more robust (read expensive) system to deal with ABS plastics for example. There is a trade off between investing a lot of capital to handle the entire plastic waste stream or go the minimalist route and obtain presorted plastics. These plastics can be consumer sorted - usually poorly done or invest in mechanical sorting equipment at the plant. Our company has chosen to go the low end which limits the feedstock supply.