Trump stopped funding this organization because it showed its helplessness in the fight against global pandemics. WHO functionaries fly business class, stay in the most expensive hotels, spend a lot of money on business trips, but the benefits of them are very, very small.
I would agree, because even now the Director general of the World Health Organization (Tedros Adhanom Ghebreyesus) looks like he is clueless about the pandemic. He caused a lot of damage during the initial months, as a result of his irresponsible statements. First he claimed that there is a low chance of the virus spreading from one human to another. Then he said that wearing of masks is not necessary. So Trump is perfectly justified in what he did.