What they were saying is anyone with experience in cannabis can tell you after a few minute of smoking if it's sativa or indica. Doesn't matter if there is no genetic definition, there are obvious differences.
There aren't, and those subjective reports can't tell us anything related to how 'sativa' or 'indica' some strain is. The only thing that affects high is CBD-THC ratios (and possibly other alkaloids) & those are independent of strain.