I'm not making the definitions up!
The ORIGINAL methodology for taxonomy classification was by observed characteristics only, and how certain animals looked and acted a lot like certain other animals.
For a long time even, things like bats were classified as avians even!
Many species were reclassified after DNA was discovered, and previously held assumptions about taxonomy were shown to be simple falsehoods.
"Vermiform" literally means "Worm like"- which is why it applies to snakes, which have a worm-like body. Your own example of an alternative usage does not help your case here.
What has happened, is that taxonomy has reached a very mature position, and creatures in (arguably very poorly named) certain categories now have very very specific features and genetic heritages, and the names have no real reason to change from what was familiar. This is an example of words losing their original meaning, and being used to mean new, specific things.
The argument is one of "Jargon" vs "Literal meaning". "Arthropod" means "Hard feet", "Echinoderm" means "Spiny skin", "Vermiform" means "Looks like a worm", Gastropod means "Stomach foot", "Vertebrate" means "Has a spine", etc.
Much like if we discovered an alien species that has a rigid spine like structure, but has absolutely no relation to anything on earth, we would call it a vertibrate, even though it does not belong in ANY of our taxonomical models! We would do this, even if it is radically alien and has no central nervous system. (Say, a distributed one instead.) This would make it CLEARLY not belong in the earth based life "vertebrate" category-- but where else are you going to put it?
Likewise if we found a cold blooded, egg laying alien creature that lactates, with genuine nipples. By definition, it would be mammal, possessing true mammary glands, even though it CLEARLY would not fit with earth mammals, lacking a 4 chambered heart, and lacking the production of a placental mass, since it does not bear live young and lays eggs instead.
In short, what I am getting at is that you are being complacent about what each of those adjective means, having enjoyed a very stable period where they have come to hold a very specific meaning in addition to their literal meaning. That changes when you start throwing in really bizarre creatures that do not fit the established categories' new implied meanings.
DF has things that are created solely out of the RNG! It doesnt obey those conventions. A giant one eyed pterosaur with 3 breasts, and a grey chitinous exoskeleton with warty bumps defies classification under your convention for use of those adjectives. Under literal use, like I have been using, you could classify it as a vertebrate mammalian arthropod. (I can just feel that making your blood pressure rise too. LOL)
I fully understand about misuse of jargon, being a former IT specialist, turned engineer. Hearing people call the system chasis the "CPU" makes me cringe-- but it isn't fully wrong either (It IS what does all the processing), just not proper use. (Proper use clarifies the individual components inside it, with the CPU having a specific definition. The assemblage is know as the "System chassis") In instances where there isn't a proper descriptor, a close but improper one has to suffice. That's the point I am getting at. We are being presented with creatures that simply dont fit the taxonomy model, but need adjectives to describe them. Using archaic and no longer used literal descriptors is what we have to fall back on. Complaining about that use doesn't make you look very open minded.