I have read that Google is dumb and potentially malware carrying extensions sometimes slip through their security and onto the chrome store. Is it true and how does it apply to Firefox
This is true and also an issue for Firefox.
It is difficult to address, and if the extension isn’t open source you should be especially careful.
That said there are extensions with security reviews performed by the Mozilla foundation and you can see that on the extension page.
https://addons.mozilla.org/en-US/firefox/addon/block-the-rich/
Irrelevant question ahead->
I have read that Google is dumb and potentially malware carrying extensions sometimes slip through their security and onto the chrome store. Is it true and how does it apply to Firefox
This is true and also an issue for Firefox.
It is difficult to address, and if the extension isn’t open source you should be especially careful.
That said there are extensions with security reviews performed by the Mozilla foundation and you can see that on the extension page.