No matter what the topic, I hope you're aware that Youtube comments are a pretty piss-poor source for information, advice, or affirmation of any kind...
In this case, the commenters are dead wrong as usual. Holding the clutch in doesn't place any extra wear on anything and won't make your clutch springs wear out early.
And as noted, there's a significant chance that developing the habit of keeping the bike in gear could literally save your life.
Once, while stopped in heavy traffic on the interstate thanks to a wreck up ahead, I felt the beginnings of a strong shove from the rear. I instantly dropped the clutch and skedaddled around the truck in front of me. Turns out the guy in the truck behind me dropped his phone and took his foot off the brake while reaching for it. The guy was mortified -- he was also a rider and thought he'd never be one of "those blind cagers"...
Upon further inspection, my Vee was entirely unscathed -- I happened to have the Givi bags on that day, and we're pretty sure they took the brunt of the shove, and my reactions kept it from being much worse.
2002 Suzuki DL1000 V-Strom, Dark Metallic Space Blue
1983 Suzuki GS850G, Cosmic Blue
2005 KLR685, Aztec Red - Turd II.2, the ReReTurdening