I believe they are used fairly interchangeably in colloquial speech. E.g.

"Full clip, do you wanna mess with this?" (Guru and Premier, 1999)

"I'm like two magazines fully-loaded to your one" (ibid.)

They're different technologies. Maybe there could be a "ammunition holding feature" superclass that both belongs. Clips don't have springs, and are used to tidy ammunition, and to aid loading magazines. Old rifles and some revolvers had clip compatibility to aid loading internal magazine. At some point the military stopped using old rifles and some revolvers, making removable magazines far more common.

But that is not even remotely relevant to the topic. The original article don't even use the word "silencer", nor "suppressor", let alone "clip".

> But most folks call it a clip because that's what movies and videogames have called them for 40 years.

This is precisely the point. Perhaps there is something illegal about these sales but why should I assume this is the case when the author incorrectly implies the existence of gun ads itself is illegal and use video game and movie terminology to talk about them?

Shouldn’t you base that judgement on the validity of their argument, and not discard the argument outright because of some semantics around the author not using ‘pure’ enough language for you?