Plausible explanation is a bluetooth malfunction where audio from some other source was routed through Rush’s set-up to the server that did the speech to text conversion and sent back what it heard.
Everything else I’ve read about this is pure FUD - or just tinfoil hat stuff that is with Ron Paul on nuttier than squirrel poop on a pecan farm scale of whackadoodle.
With the amazing, mind-blowing technology we have today, it is not "whackadoodle" to realize that the ability to hack into systems like Rush's (or any systems for that matter! Pentagon?!) most certainly exists, and that is the very least of capabilities. To underestimate the powers that be is pretty whackadoodle.