The second one is an "Assault Weapon", not Rifle. This is why it was called the Assault Weapons Ban.
See [0], "a United States federal law which included a prohibition on the manufacture for civilian use of certain semi-automatic firearms that were defined as assault weapons".
"The Act prohibited the manufacture, transfer, or possession of "semiautomatic assault weapons," as defined by the Act."
0: https://en.m.wikipedia.org/wiki/Federal_Assault_Weapons_Ban
People use the term "assault rifle" to mean "assault weapon rifles". It is a very widespread usage, including by politicians and the news media. It is also a very logical usage – it is simply shortening the phrase by dropping "weapon", which is kind of duplicative given it includes "rifle". Yes, this contradicts with the older military usage of the term "assault rifle" – but different people use words in different ways, language evolves, and insisting other people are wrong for using words differently from how you do is just ignorant linguistic prescriptivism.
It is, but it actually has two different meanings. There is what you mean by it (the traditional military definition) and then there is “assault rifle”=“rifle which was legally classified as an assault weapon under the 1994-2004 US Federal Assault Weapons Ban”-a civilian AR-15 is (generally) not an “assault rifle” in the first sense, but it is in the second. Now, you can argue the second is an abuse of language - but once a usage becomes supported by US federal law (even if since expired), that becomes an ipso facto legitimate definition, and it would be better to acknowledge people who use that definition as doing so than lecture them that they don’t know what they are talking about (maybe they don’t, but when you don’t acknowledge the different definition of the term which they are actually using, it doesn’t make you sound like you do either)