I would bet real cash money that many many people, including your coworkers, think that anyone who unironically uses the term "midwit" is completely and totally obnoxious.
But I don't remember how he defined a midwit, because podcasts are a terrible way to convey knowledge. It might've been something like someone who acts like they know everything.
Workplaces are where many of us spend a large percentage of our waking lives. So, it is "normal," unfortunately. This is why HR language and norms have broken containment into the non-work world. (Whether that's a good thing is another question.)
There is not one single discourse norm to rule them all and calling out every little thing as too offensive is just annoying. Yeah, yeah there are no midwits, everyone is a unique little genius flower, yeah.