The cited usage refers to the metaphoric image of an oppressor having his boot / heel on the throat / neck of a victim (the hapless victim can't move / breathe). The implication here is that the current economic system is responsible for this oppression (so it needs to be "rebuilt").
The reference to restoring our autonomy (giving us back our independence / freedom) suggests that the writer is part of some socially / economically disadvantaged group seeking the freedom to make their own choices. Specifically, so they can focus on things like combating climate change, rather than social injustice.
If the victim (with that metaphoric boot on his throat) could speak, he might say Get your boot off [of] my throat! As this NGram for Get your hands off (of) me! shows, the second preposition (of) isn't normally included in such contexts. Arguably the "double preposition" form is slightly more "emphatic", but it doesn't really make much difference - it's just a stylistic choice.
Also, because it's an important part of Anglophones' linguistic heritage, I can't resist flagging up George Orwell's closely related metaphoric usage in 1984, where he characterizes his dystopian future as a boot stamping on a face forever.
Finally, note that native speakers will be divided as to whether the cited usage should feature singular off of our throat or plural off of our throats (see “On their back” or “on their backs”? as asked on ELU some years ago).