many oomfs on my tl are confused and i hope i can help a little in understanding the situation. yes jaemin did use 저능 (ableist slur). what is unclear though is if it was a mistake or used purposely as a word play with 저명 (famous/well known).

yes it can be very easy to mistakenly mispronounce one word for the other. it could have very well been just a simple mistake.

my opinion on the situation:
to me yes it seems more like jaemin made a mispronunciation mistake because it sounded more like he corrected himself in the video. but does that excuse their behavior?

honestly i am more upset at the way the other members handled the situation. i do not think it was appropriate for them (jeno, jisung) to repeat the word and laugh (renjun, chenle) at the term making it into a joke.

i can not tell you how to feel about this situation and whether you should be upset or not. it is up to you to form your own opinion. this was only my own opinion and you do not have to agree but i hope i was able to clear the situation a bit.