I'd have no issue with it. My oldest sleeps over at a friend's house quite often, and it's just the boy and his mom. The thought of anything happening has honestly never even crossed my mind.
I had friends sleep over all the time when I lived with my single dad. Actually I had a lot less sleepovers after he married my stepmother.
That said, I do believe I understand what Gloria was sharing re: her dh's decision as a single dad. I could understand someone being hesitant to put themselves in the position to be potentially accused of something inappropriate -- particularly if he does not know the kids or parents involved in advance. While I *get* that it would be unlikely with so many present as you'd think that the others would serve as witnesses, unfortunately there are those few kids... particularly in the preteen/teen set... that *may* use an accusation as a means of getting attention, or perhaps even if they didn't appreciate the house rules, acted out of jealousy, etc. Again -- I do NOT believe that would happen in the majority of cases, but the thought if that "1" just happened to land in his home it certainly could serve to give him pause. I know many youth organizations caution from not having another adult present in situations that would not be considered "public" for the same reason.
I'm sure at times, Gloria's step-daughter may have been disappointed but it doesn't sound as if he isolated her from having friends over... just not to sleep (granted maybe I misunderstood?) -- nor did she say that the sdd was forbidden from going to a sleepover. He sounds like he simply made choices to protect and insure that he was there for his dd for the long term vs. putting them in a situation that -- despite best intentions -- could be misconstrued. Is that *fair* thinking? Not really - but I think most of us likely object to some of the new realities our kids face that our parents didn't think twice about.
This may make me a terrible parent, but I don't have time to get to know everyone else's parents in such a deep way. My kids don't do sleepovers yet -- Juliet's too young and Nathaniel, although he's 9, doesn't want to -- but I am not a stay at home mom so my time is really limited. I know many of the parents on sight or for quick chit chat but there are only a handful I actually know "well". I would still let Nathaniel stay at someone's house if the parents didn't fall into that category.