Earlier quoted context omitted.
An honest UI might use the word “echo” rather than “retweet”.
Retweet used to actually retweet things (i.e. pretend "RT" and the OP's handle), so it's like the floppy disk icon. Parler uses a megaphone.
And then the platform owners mostly misunderstood the problem and emergent solution, and natively implemented something similar but optimised for advertising sales metrics ("engagement!") instead of what the users were actually doing.
And then as the user base changed from it's early-userbase to being heavily biased to marketers (sorry, "influencers" and/or advertisers), and social media expert gurus started talking about "message amplification" - and so we end up with new contenders in the field thinking that the lack of ability to shout "brand messages" through a megaphone was the problem those early users "invented" retweeting to solve...
(And now I'm imagining a world where a St*rbucks-like cafe chain hands megaphones to everybody as they enter the store, with the implicit understanding that you shout out every interesting bit of conversation you overhear, which inevitably quickly develops into people only shouting out other people's megaphone shouts because that's all you can hear, until eventually if crescendos into a Hendrix-esque never ending earsplitting feedback wail - probably Star Spangled Banner for maximum crudeness... Has Black Mirror done this yet?)