I feel like there are multiple threads of thought here.
We need to win a trophy and any trophy is good gang: I don't think even they really believe going on a deep run in the league cup and potentially winning it is a big deal. Klopp asked his assistant to take some U-23s and compete in this cup, that's how little it matters. Doing a brutal two legged semi final right in the middle of the fixture period? No thanks.
We didn't / can't give youth a chance: Yes, but I don't think it would've mattered if we played Hannibal instead of Mata and Elanga instead of Martial today. And even if we won, it's another two games where they would've been given chances (R4, R5). Once you're in the QF, you have to take it seriously and play the first team. 1-2 additional 90s for Elanga would be nice, but it's not that big a deal.
We shouldn't have played the reserves gang: You seriously don't believe in VdB, Matic, Telles, Dalot, Henderson etc. deserve competitive game time? The only players you can argue about is minutes for Mata / Martial. I'm sure these posters will be the first to blame the club when we sell Martial and he does well in the French league. We know there's a good player in Martial, give him a fair shot and get rid if it doesn't work out. This was a pretty big opportunity for Martial and he didn't take it. Ole knows very well what he's doing here.
Standards are dropping gang: We rotated literally the entire first XI and asked a team that has barely any cohesion / match fitness to go out and play. And they outplayed West Ham. If you're a mentality monster / win at all costs types, then you don't get to complain about patterns of play or expected goals when we win dirty.