If the tags are there in metadata, I would argue that showing them is a good and proper approach for Amethyst. Otherwise, I might think there is a bug in the tag specific stream I am subscribed to when I see your posts present without the tag.
I meant its Amethysts choice at the end of the day. If they are fine with their users experiencing NOSTR differently from practically any other client, so be it. In my particular case what is interesting is that those additional tags are unintended and are somehow included at some point of post creation through Shipyard.