The reason Trump is calling it the Chinese Virus is simple.
Chinese officials have been making outlandish claims that the virus is of American origin and that a US military delegation that visited Wuhan was the source of it all. The Chinese are trying to put the blame squarely on the US.
Calling it the Chinese Virus time and time again, is Trumps way of making the world know the virus originated from China and is not of American making. (This is especially for the countries that have a dim view of the US and are prone to believing all sorts of Chinese propaganda).
That is the reason why he is calling it the Chinese Virus but I guess it’s easier to say the orange man is a racist.