Such a weird recommendation. It's so variable. 8:15 would be perfect for me (2 year old and 2 month old at home). 8:15pm is after bed time. If the dinner started at 5pm, it wouldn't work for some parents, and for others 5pm might be way too early.
You can't please everyone, and sometimes trying to is worse.
You can't please everyone, and sometimes trying to is worse.