I understand where your confusion comes from: the verb seemingly agrees with the preceding noun which you mistook for the subject.
This sentence is actually of a special kind called неопределённо-личные предложения ("indefinite person sentences"). They have no subject and the verb is in the third person plural:
В зале поют. - There is singing in the hall.
Мне сказали принести это сюда. - I was told to bring it here.
Мне принесли эту книгу. - Someone brought me this book.
Ему здесь всегда рады. - He is always welcome here.
The subject is not mentioned because it is not important. There are a few ways to render such sentences into English (which normally requires a subject): using the passive voice ('I was told'), using an indefinite pronoun ('someone') or restructuring the sentence, see above.
Although the predicate is plural, it bears no indication of number. E.g. if you are told:
Проходите, вас ждут. - Please come in, they are waiting for you.
From this phrase alone, you can't deduce how many people are waiting for you, it could be one. Another example:
Что делать, если говорят, что любят, но замуж не берут? - What do I do if I'm told that I'm loved but never get proposed to?
Despite of the plural, it is obvious that the person does not want to marry many people at once.
Back to your sentence:
Зимние игры называют Белой Олимпиадой.
называют with no subject is a common way to say what something is called. The subject (who is doing the calling) is not important.
называть takes two complements:
называть <кого-либо/что-либо (Accusative)> <кем-либо/чем-либо (Instrumental)>
to call <something> <something>
Зимние игры fill the accusative case slot in your sentence. To make this more obvious, one could also say:
Олимпиаду называют зимними играми.
Олимпиаду is in the Accusative and
зимними играми is in the Instrumental case.
N.B. There is also безличные предложения (impersonal sentences) which are slightly different from "indefinite-person" sentences.