“Once you label me you negate me” is a quote attributed to Kierkegaard. It isn’t fancy like some other Kierkegaard quotes, quips, Japes and Insights. It certainly isn’t his best statement overall, if indeed he even said it. Perhaps he titled the work in which it was written and then it disappeared.
If someone could label me in the sense that I was perceived by the populace of the entire world in a unified way, even if that viewpoint was derogatory, I would still know my personal worth. Although I must say that even the strongest among us may be a tiny bit swayed in their feelings of self worth either + or - based on the opinions of others. But, I would think negation would come in a more complete way, it is NEGATION after all.
A label does change a thing, a can of generic soup vs. a can of big name soup (both made by the same manufacturer out of the same ingredients) will experience very different cupboards in very different homes for several years until someone finally opens them and purges their contents thus negating them.
As for the general use of this quote, I’ve always thought of it as a whiny statement, a pre-victimized perspective, as though anyone could just walk up to you and negate all your worth (assuming you have some).
If you allow someone to label you then you have most certainly opened yourself up to the possibility of some variety of personal negation.
I think it is more to the point to say, “if you freely associate yourself with a moniker of questionable worth, you have placed your value in peril.” We don’t have complete control over our existence but until I am given a label over which I have no control whatsoever, such as “corpse”, I will present myself as an independent entity. I will avoid established labels as much as reasonably possible. When I create a label that is assimilated into the vernacular, I will disown the label at its point of saturation.