Considering audience engagement, people shouldn't get too stuck on the actual numbers. The 40% most likely aren't to be valued at exactly 40%, because you can't properly scale such diverse values and compare them to each other to get hard numbers. It basically just means it gets taken into account, but the judges decision has more weight to it. Popularity will help with a decision, but it won't be the mayor factor.
It's like owning 51% of a company. Everyone else can give their opinion, but in the end, the big fish got the last word. They mention a high number for audience engagement to make clear they understand that you have to listen to the audience to some degree. It's basic logic in entertainment that you need to cater to the audience, not the other way around.
We don't know their pointing system. Nobody said you will get points in popularity to get added to the points you get from the judges to do some simple math. It's highly unlikely to work this way.
This is a beautiful and inspiring mindset. I wish way more people would share it instead of getting discouraged. Of course, winning would be nice and numbers can be harsh, but we should focus on doing our best and improve instead of seeing this as a one way track.