Labels are definitely unnecessary, but can be helpful in certain contexts. Like here on RF.
Without a label, if you enter discussions (and for sure debates), people will label you (which is how I hear
@Mestemia 's point). If they mislabel you, you'll let them know, but that is probably going to lead to another label, as it is fairly likely whatever you're currently speaking about has been discussed previously, and thus a label can be attached to it.
I don't think the label becomes us, or if it does, then we also can expand the label, whether or not those stuck on stereotypical characteristics (previously) associated with that label like it or not. So, if you are an atheist that has high appreciation for Bible and Christian history, then there is at least one atheist existing that has those characteristics. Another hardline atheist may think that sucks, but that is entirely on them. Just as all the bad / contradictory stuff that some religious people do sucks to some (or many theists), but those judgments about that type of theist are on us who think that.
In most cases, I think the label is a temporary consideration. Helpful a bit in a debate/discussion or helpful perhaps if wanting to have congregation and not exactly welcoming everyone - essentially looking to accept into the fold those that aren't seen as intentional disruptors who are looking to sabotage things.
Labels are really about the roles one may play in a situation. Being an atheist and say wishing to play forward in a soccer match, really doesn't matter (at all) if you are atheist. If you are on a religious forum wishing to debate characteristics of a deity, the label atheist helps save a whole lot of time in what you might be trying to get across if you were without a label.