The “just look at them” test is probably more reliable than a genetic test. Nobody would claim that a specimen of Homo hela is a person, but genetically it’d be almost identical to us, having diverged from Homo sapiens less than a century ago.
This same thought has been used to justify, far too many times, that black people are more apelike and thus less human. It was almost certainly also a contributing factor to the extinction of neanderthals. Visual similarities have no actual bearing on speciation; a chihuahua doesn’t stop being a dog just because it looks so different from a husky. Visual similarities have also led to many species being misidentified as related when it’s just due to coincidentally convergent evolution. Taxonomy is a collection of mistakes of visual identification that are only slowly being corrected due to better understandings of genetics.