It’s always easier to chalk up your bad SR and blame smurfs and throwers, like 90% of ladder players below GM do (ofc I pulled this out of my butt, but we can all agree that players tend to do this a LOT). Just take the blow and go on with your life.
But let me tell you a story. I bought a new copy of the game like two years ago, but before you guess, I was planning to play legitimately to the best of my abilities (and I still do). In qp I pretty much stomped the other team on my then-main Tracer, and promptly got called out for smurfing. For the first five games tops. After that, I got matched with and against shiny borders all the way until level 25, and ever since I’m playing comp and warmup arcades exclusively on that account. But, until I reached my first star under my portrait, gold and plat folks kept calling me out (and probably reporting) for smurfing, despite my best attempts to play as good as I could in every one of my games. I improved a lot since then, so I’m not saying there were zero pubstomp games in the mix, but within a couple games the matchmaking system balanced me close enough to my main SR range so that’s that.
However what I saw a lot was countless players explicitly throwing games, because “we already have a smurf on our team so whatever”, lo and behold 5 dps + me as Moira. For an entire night once. Those people had roughly the same attitude as OP and commenters supporting OP, and they legit thought that anyone below level 100 cannot play the game (somehow when asked why plat border players are in bronze, they couldn’t answer), one of the guys - level 700-ish, silver border with one star - even claimed that he was only playing comp since level 25 and he climbed only 200 SR during that time, not believing anyone below 100 could be anywhere near plat. I also had some guys telling me that as someone below level 100, I should play supports. Sure enough, after my 3rd slept nanoblade they called me out for smurfing.
So what’s the moral of the story? There’s none. Simply don’t judge players by their level, because it doesn’t mean a thing in Overwatch, it never did. If that guy is a legit new player on your SR, let him play what he chooses first, because likely it’s his best or near-best hero, or if it doesn’t suit the map or the comp (eg. choosing Widowmaker into a close-range comp with let’s say Rein-Zarya and Moira-Lucio, or playing Junkrat on Nepal: Sanctum where teams tend to play Pharmacy), explain them to the best of your abilities over comms why you think it won’t work. If it’s a smurf account, only report once they already threw the game, since it doesn’t matter if you report them at the start of the game - you’ll likely lose either way with a downranking smurf in your team. Also that being said, I don’t think I ever had a thrower smurf in any of my games (probably two at best), I simply know I have plenty of room for improvement
Oh yeah, and I also have a third account currently sitting at level 25 where I am only playing Genji, Hanzo, Zen and Rein, neither of which I can play, and on that account I also got called out as a smurf. I mean, not all new players are clueless, when I first started the game in December, 2016 I already played on both free weekends, watched hundreds of hours of compilations and analysis/coaching videos, so despite my… let’s say mediocre mechanical skill and apparent fondness of Junkrat, I knew most flanking routes, cheeky trap spots and hero counters, but smurfing was yet to become the red herring of salty dudes on the forums at that time.
Ps.: sorry for the clunky wording here and there, apparently on Blizzard forums the letters ‘C’ and ‘K’ cannot be written together, wth…