I think I do understand where you're coming from. As if you're trying to find your way around, and I'm suggesting not to use signposts! :-)

I agree that describing is important to identification, but I don't see "left"/"right" as descriptions so much as labels. Description is a more thoughtful, less reflexive process than labelling. It does takes longer, but it is more informative.

In the directional sense, extreme left and right are 100% opposite, but this isn't true in the metaphorical sense, so the metaphor is a polarising perspective. Similarly, the political "left" and "right" disagree among themselves on plenty of issues, which the label helps one to overlook.

The name "Antifa" is a contraction of "Anti-fascist", isn't it? What is an "anti-"fascist? Some who opposes all fascists? Or all aspects of fascism? Does the group have positive policy of itself? Is it, for example "pro-immigrant"? OK, this is a label, too, but a more descriptive one. Does it favour higher taxes or less income inequality? If I had to refer to their orientation in general, I would describe them as a (self-styled) "left" group (in quotes), meaning that the label is suspect. I would generally try and avoid discourse in which a single word (or just a few words) was all that anyone wanted to know about the group.

Avoiding the terms "left" and "right" makes political discourse more long winded, but also multi-dimensional, which I've found to be extra effort well spent. It's important to notice, for example, that far from being opposites, the long established political parties are more or less identical on a whole range of key issues, such as the need to keep fighting the War Of Terror.

The extended answer to this question is at https://www.unwelcomeguests.net/, a recommended radio show/podcast that makes minimal reference to the political spectrum, especially the episodes since 2010. I know that material fairly well, so if I knew more of you're angle, I could maybe recommend a specific episode.