Yeah, that statement is an oversimplification of an oversimplification. The idea behind it philosophically is that it is far easier to prove that something exists/is happening than to prove that it is not. Essentially that if someone is going to make the claim that google is doing X, the proof is easy: a single instance of it happening. To prove google is not doing X requires you to create a collection of all of googles actions, prove that it is a full collection of their actions, and then prove that within that collection exists what the topic of debate is. Therefore, while it is not technically impossible to prove that google is not doing X, for the purposes of debate we should treat it as if it is and the burden or proof should rely on the person claiming that google is doing X.

Of course, as people living in the world we don’t necessarily need full proof to try and protect ourselves from the actions of an entity we don’t have full knowledge of. But saying “I don’t want to give google X data because of what they theoretically could do with it” is different rhetorically from saying “I believe that google is doing X with the data, and if you don’t prove otherwise it’s probably true.”