You forgot to mention the build and strat only really works most effectively vs tank toplaners. Bruisers will contain you for much of the game and you'll have to play hide-n-seek to dodge them later and push tower or they can probably kill you and the minion wave mostly negating your strat. And fighters? They'll do what bruisers do only better later in the game.
People use literally everything as an excuse. The majority of people just watch a vid or google crap and run it because they think it's good. Sometimes it is, sometimes it isn't; regardless, they tend to have no clue WHY it works and so they fail with it miserably or play it very sub-par. Because we defend these people and admonish any form of negative feedback - even if done so respectfully - (like bot, you can't win 2v2 right now, please just farm by your tower for now) these players never learn. It's one thing to make a mistake here and there - we all do. It is another when you see someone making the same mistake 3,4,5...10+ times in ONE match. Like does someone have to tell them every damn time they cross the street to look both ways? I'd like to think not. So neither should they need someone to point out it's a bad idea if they fail the same thing 3x or more. Learn... because it's no longer a mistake - you know better. But we excuse these people and punish anyone who dare point out that they need to stop no matter how nicely they explain/ask. And this only serves further to hide people who are hard inting like you mention above and excuse it because we've created a community where pointing out anything bad someone has done (even politely in the interest of helping them improve for next time) is considered toxic. As much as people claim nobody understands what inting is... nobody understands what toxic is.
I'm amazed how many players can have things explained to them very clearly and logically - backed up by facts and examples - and appear to have 0 understanding of what was just said to them. And how freaking blind people are. The perfect example I run into way too often? I'll warn my team several times with pings, type in chat, and go to clear a giant side wave so they know not to get too close and get caught out 4v5 or engage a potential 4v5 fight. As soon as I get wave cleared and building up to slow push to enemy tower? I'll look to group. Only... my teammates ignored everything I said and pinged, forced a 4v5, and died before I could even finish tp - even when I start it before touching the wave cuz I saw they went in anyways. Team all dies, team blames me, team loses game. Utter stupidity. But it gets better. Adc or support runs off without warning as we are about to fight because we NEED to force to defend a game-ending baron or elder? Team (me included cuz I'm prioritizing objective and TEAM over selfish farm) engages 4v5 or gets engaged on, team gets wiped, someone from the 4 man is an "idiot" who cost the game - not the adc or support who ran off to afk farm when we HAVE to teamfight in 3 sec or basically hand the enemy the game for free. Now there's logic lol.
I swear the intelligence level of the typical gold elo player is now where it used to be in bronze... when I started 4+ years ago. There's far too many players who are hella boosted... probably across the board (all elo's). People need to stop excusing this crap as "bad game". If my micro skills and champ mechanics are far below par, my macro is abyssmal for my elo, I refuse to work with team or adjust from making the same bad play(s) over and over again all match long... I'm clearly not just having a bad game. Bad kda does not equal inting, but underperforming by a landslide in every measurable aspect of the game while refusing or proving incapable of adjusting my poor play would prove that I'm highly boosted. These people should be punished. And monitored. If they keep doing it even if it's just a few games here and there... but consistently, they should be insta-demoted a tier or two to the elo that matches their play. I know people are gonna downvote this because they'll think I'm saying a bad game here or there is going to drop them from silver to bronze or something. But that's not what I'm saying at all. I've had teammates start 1/7/0 in laning phase, but they listened to their teammates, worked with them, and ADJUSTED/IMPROVED their play throughout the game. They made an obvious effort to work with their team, make SMARTER plays, and TRY to win. You do that? You aren't repeating the same "mistake" over and over, you aren't intentionally sandbagging or playing boosted all game long. So you shouldn't face any punishment for that. If you were to go 1/7/0 in lane, keep making the same bad plays, refuse to listen to teammates, never adjust your play, have terrible mechanics for your elo... that's a different story.
So in summary: there are massive problems with boosted players (or intentionally sandbagging players) ruining games for other people, inting sion strat can be an excuse to hide this - which is furthered in it's effectiveness due to the overprotective culture we've created, and sion strat is most effective vs tank toplaners.