As Rich says, this is not a ban on race. It applies equally to all passengers originating in China.
Any passenger - anywhere in the world - should defer travel if they are positive. A test shouldn’t be required for this to be actioned. Therefore a test shouldn’t make any difference to those intending to travel, as they wouldn’t be anyway.
We can be relatively sure about data coming from the UK and US. We don’t have the same confidence on data from China. There could be a new variant which we’re not being told about.
How can you be relatively sure about data coming from the UK? I live in the UK and hardly anyone tests anymore - sick or not. So explain to me how that gives you confidence in terms of data?
Again, there is a dangerous variant - what have you or ay government done about it?