The reason 'Taiwanese' is used to describe the dialect of Taiwan people of Fujianese ancestry is not because they were the first to come to Taiwan, nor because they are the largest ethnic group in Taiwan. It is because their originally Fujian dialect long ago established deep roots in Taiwan.
台語之所以會成為閩南人的專屬，絕非他們早已先入為主；也並不為了他們是台灣最大的族群，而是閩南語在台灣早已根深柢固了。