Unless your home defense gun is the family's old matchlock musket, or more modern but still older single barrel shotgun or double barrel side by side shotgun, with no sling options, then you might have excuse. All your home defense long gun(s) from 1970's onward were likely built with sling mounting options. Which you should use, because why would you handicap yourself on the worst event of your life?
Even the older guns have had modern part adapters made for them. Uncle Mikes filled a niche market, and was the go to Brand option that many look down at today, to allow you to install sling studs into the wood or add a clamp bracket around the barrel(s) and possibly a magazine tube. Back when manufactures didn't include them as the default.
This not having a sling , is like the debates of I don't need a Weapon light, I'll just turn on the lights in the room, What if the power is out or has been disabled, ever hear of looting after a storms? Like Hurricanes, Tornadoes or Massive thunderstorms..... Always more pro's than con's to having one.
Don't forget the older people that are still rocking the same home defense guns they had back in the 1950's, 1960's, 1970's and 1980's. Be it their basic classic Double Barrel (the Biden Special), an old revolver, that they never bought those fancy speed loaders or moon clips for, and/or a lever action. They're not your typical poster here, they may never go online to gun forums. They exist and how the set up their home defense guns is just as important to think about. Shocking as this sounds, this forum does not represent the majority of gun owners, even as diverse as its membership has become...
Now debating the subject of why the hell do modern Slings cost so damn much for some damn webbing and a slider buckle, is worth debating.
The irony is most people pay for all this quick disconnect hardware then never use it. Then again that is like this whole thread, it is better to have the option and never need/use it, then need it right then and not have it because you were cheap and lazy.