[QUOTE=Darwin’s Finch]
So, in a lot of ways, the distinctions being made today are the result of refining the way we think about relationships. Linnaeus was a creationist, so he grouped organisms together based largely on appearance, or modes of life, rather than any actual relationships. Today, we try to group organisms based on relationships, and the result is that a lot of older definitions for things like “bird”, “reptile”, “amphibian”, “dinosaur”, etc. wind up getting re-worked in the process.
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That’s all well and good, but it sure makes it hard to be an interested layperson. 
I note there is a broader classification called “mammaliformes”, which includes the mammal ancestor and the clade to which Castorocauda belongs. So one could argue it’s a choice of which word is used where.
But yes, I see your point.
The confusion comes in with things like saying birds are “reptiles”. You’re leaving a lot of laypeople in the dust. But I suppose it’s no different than the IAU declaring that Pluto is no longer a planet.