The purpose of the Miller-Urey experiment was was to prove that complex organic molecules can be created under certain environment conditions, without any need for supernatural interventions by an external intelligence. I think we can all agree that this was the outcome of the experiment, regardeless of semantic discussions about what "guided" means.

Whether the original earth atmosphere or electrical energy was matched by the experiment can be disputed. However, amino acids were also created in experimental variations of the atmosphere and other parameters. We're finding them even in meteorites, so obviously they form under a wide range of environment conditions.

While the precise composition of the early earth atmosphere is not yet 100% clear, we know that it contained water vapor, hydrogen, carbon dioxide and carbon monoxide, but no oxygen. We also know that UV radiation provided the energy to break up H2O and CO2 molecules and create organic monomeres. And liquid water provided a protected environment for the building of polymeres. So, everything theoretically required for abiogenesis was there.

The Miller-Urey experiment produced 13 of the 21 required amino acids within a few hours in a small pot. Organic polymeres had hundreds of millions of years in a much bigger environment for evolving self-replicating proteins.