I mean the vast majority of the victims are Asian and it was Asian establishments that where targeted, so why wouldn't it be racially motivated. It's like shooting up 3 Yeshiva's and saying that religion/ethnicity had nothing to do with it.
Also for him to assume that 60+ year old women at massage parlors are sex workers is racist in and of itself
Unless we are assuming here that he knew for a FACT that each one of those individuals are sex workers it's impossible to claim that race wasn't a factor in the attack.