– “Let’s grow food for cars (bio-fuel) instead for people. I don’t get bio-fuel either.”
The bit making it nonsensical is “cars”. We could do without most cars or run them on batteries, but to produce and distribute enough food we are dependent upon combined harvesters, tractors, trucks, freight aircraft, chainsaws etc., and so far only combustion of liquid fuels has high enough energy density for these.
When these are run on fossil fuel they increase the atmospheric concentration of carbon dioxide by moving carbon from underground into the atmosphere, thereby increasing global heating. If however they’re run on biofuel, the carbon is initially obtained from the atmosphere by photosynthesis as the feedstock plants grow; thus it does not add to atmospheric carbon dioxide overall.
The trouble is that growing the feedstock plants requires extensive land area, whereas extracting and refining oil need hardly any land in comparison.
Land area is also an issue with solar panels because most crops need direct sunlight. But there is still far too much roof area going to waste. I recently met a bloke who’d lost his job putting up solar panels because government policy changed.