Earlier quoted context omitted.
I tried searching for what a "lifestyle fee" is and all I could find is references to "living wage fee" which is essentially a forced tip added to the bill. A service charge for large groups though is understandable as they typically will require much more attention and work from waitstaff than the typical small dining party.
I'm somewhat skeptical that they actually require more attention per person . Does an 8-person group require more than 2x as much attention as a 4-person group?
They’ll take longer per person to order because they’ll be coordinating appetizers and who’s sharing what, etc.
They’re more likely to be celebrating a special occasion which means people less familiar with the restaurant or even people who don’t eat out much at all.
And the group is big enough that people will be having side conversations while one side of the table talks to the server, which also slows things down.