That’s not even close to true.

There’s tens of millions of people with that name. The WHO did not want to stigmatize all of them which is why they skipped the letter. It had little to do with Xi Jinping alone.

The WHO moved to Greek lettering to avoid stigmatization faced by people who were being associated with different variants. It wouldn’t make much sense to do the same when you can avoid it by just skipping a letter.