75F would already be a warm room for many. 70F or 21C is usually room temperature around here. In the past this was often 65F. In more southern places 75F is middle of the night temperature and too cold.

I can see how the F scale makes some sense, but then you see some news report from Texas reaching 100F and you wonder if people can read their own temperature scale as that is clearly not fit for human habitation.