I can’t. I do not decline people for being under-age. We have never had any issues with them being in the group or being able to interact with people on the group wall. From what I can tell, this update is trying to combat issues related to open, free join groups that have issues with inappropriate posts and bots, not groups with actual moderation.
It’s really not too bad when you have done it for as long as I have. I can go through hundreds of requests without much sweat. I can understand why someone might have trouble doing it quickly if they are not used to it, but if you assign more than one person to do them, it would be a complete breeze.
Looking at your group, it looks like a UGC group. Our groups are, then, fundamentally different. I own a war “clan” group, if you will, that has daily events in our game and basically requires community interaction. This is why groups like mine have more use for the group wall feature than groups that exist to sell UGC items or exist to host a game on them, both of which are, I assume, mostly used for community feedback and for people to post their ideas.