It's weird, but it's not much we can do because it serves the plot I guess. The only argument that could really be made is Escanor in his Dayman form just can't be read, due to his perspective on life, similar to how he was immune to Estarossa's commandment.
I think they are supposed to be strong, but they've been put into situations where they haven't been able to demonstrate it properly. Right now, we are only seeing King and Diane piloting their bodies. They can use a bit of their power, but they don't understand the intricacies of it. At least, I'm hoping that is the case. Glox is a Commandment I have high hopes for.
It's possible Dahlia will show up in this flashback, as we should be getting ready to see how Glox and Dolor defected, meaning the Fairy Forest will need a new King.
I was debating that myself. Angel Clan works for me...unless we find out that they really are all women. Anyway, immunity is also possible.
