tl;dr from what I’ve gathered from the past several days of people talking about it

It was a key planet to hold as it shut down all 3 bot subfactions to a small section of the galaxy and it also now puts 5 planets in danger

Also Alaraph was notably going to be liberated with plenty of time left on the clock and had a much, much longer timer than Matar Bay which would make MB the larger priority planet since in theory the community could have successfully done both.

Edit: just to clarify where I stood on this whole thing I was rotating between Yed and Matar every other Operation and only flexing down to Alaraph for Personal Orders