Objective differences doesn't have to mean physical differences of the thing at the time. It is an objective fact that certain people have won elections and that others have not, for example, even if it doesn't change them physically.

In this sense, it is true that every meaningful distinction is based on something objective, since otherwise you would not be able to make the distinction in the first place. You make the distinction by noticing that some fact is true in one case which isn't true in the other. Or even if you are wrong, then you think that something is true in one case and not in the other, which means that it is an objective fact that you think the thing in one case and not in the other.