24 fps not Hz, no TV on the market uses 24 Hz as its display rate, or ever did, LCD panels are a single light source, it would be unwatchable at 24Hz due to flicker, your TV is displaying them at 2, 3, 4, 5 or 10 times that rate depending on age and technology.
There are projectors that can run on 24Hz without flicker but that is because they are multiple light sources but even the digital movie projectors used in theaters use 48 or 96 fps even though they are dual light sources.
That HDMI is sending the signal as 24Hz does not mean that they will be displayed as such