Last year they had to remove downforce in order to get the car driveable. By the time of Abu Dhabi, the moment you are referring to, they found ways to run full rear downforce again. This meant they didn't have a correct type of wing, and because it was so late in the season, it mattered little to design a new wing with more downforce. Also note they struggled back then with front downforce, almost unseen in nowadays f1 as the limiting factor is rear downforce, the issue they are having this year.This year we see a McLaren with a inherent lack of downforce, the 2013 car had the same issue. The front-wing is maxed out and the drivers are still complaining about the lack of downforce. The lack of downforce means that they can't generate as much G-force the keep the tyre in the right window. Thats why McLaren was almost 2 seconds slower during qualifying then Mercedes on a high downforce track like Suzuka. ScarbsF1 explained that in one of his latest video about updates.
The 2013 car never had a shortage of peak downforce, the issue was they rarely could use it since their diffuser was stalling. They had to remove downforce. Oh wait turbof1, does that sound familiar? Yes son it does, mercedes did the same in 2012.
The current car indeed has a lack of downforce. It's still a learning year. They'll get to it. The biggest releave is that they aren't facing the same issues as last year: the car is very stable! Last year they came to realisation their concept of front wing wasn't working (I personally think it didn't redirected the airflow well enough in order to get better vortices sealing the floor). In Spain they slapped on a wing that was better at managing airflow structures, but had much less AoA. This year you see them running much more angle and much complexer wing.