I feel that a Horologagnostic would be someone without a knowledge of the workings or instrumentation of clocks, rather than having an inability to read the time. I'd prefer a "chronometro-irrecognitive" made up from 'chronometro' = 'clock or chronometer' and 'irrecognition' = 'a failure to recognise', or, 'absence of recognition'. But we should remember that this condition could be brought on by the fear of clocks in people with Chronomentrophobia. (And please don't ask me why the medical establishment saw fit to introduce an extra 'n' into 'metro').