I think it's a combination or operational needs and geopolitics.Yes..Liaoning has been in commission for what? Eleven years. The ship has not ventured very far from the shores of China.
Liaoning though fully combat capable is for the most part a training carrier so they will probably operate within the 1IC or at most 2IC.
As to the other, I think CCP/PLAN is probably wise as this point to not venture too far or go faraway port visits.
With much negative press on China these past few years and a carrier being a strategic offensive weapons platform, it'll likely attract very negative press in western MSM even if the port visits are benign and friendly.