It is common knowledge that Lindelof is weak and Maguire is slow, and that they both face huge problems whenever they're asked to defend bigger spaces, either in front of them//behind or in the wide areas. There's no use beating a dead horse. The ultimate sign, the other day, which points toward Lindelof's lack of quality at this level, wasn't his decision-making as much as it was the simple fact that Ollie freaking Watkins made him his bitch in the entire game.
Other than that, there's no basic principle saying that the centre-half has to give away a foul, which will result in a crossing opportunity and will bring most of the outfield players inside your box. Not when there are defenders behind that can still cope with the situation. Really, none whatsoever. The professional fouling, that both Pep and Klopp love so much, occurs higher up the pitch, its purpose is to prevent a direct route to goal and it allows the players to get back to their pressing positions when the play resumes.
The thing is, we know the deficiencies of both Victor and Harry. We have to live with them, since it's impossible to assemble two world-class starting line-ups. What hurt us on Sunday is that the pressing fell apart with Ronaldo and Beek, leaving acres of space for AV to exploit, and that our game with the ball leaves so much to be desired that every mistake that happens at the back seems like a catastrophe of epic proportions. Well, the mistakes centre-halves and goalkeepers do are often scrutinized because they usually cost goals. But defending is something the whole team has to be involved in. You know what i see when i look at the first goal: A Rashford who's initially thinking about helping Lindelof (which would have forced them to stay wide or go backward) but then decides "nah, feck this shite, it's beneath me". An Eriksen who has absolutely no clue what's going on behind him and makes the wrong decision. A Dalot who falls for the decoy run and then never bothers to tuck inside. Lindelof assessed the situation correctly, he just couldn't cope with the attacker. But that's who he is as a player. The team and the manager have to make up for that whenever Varane isn't available.
As i said, both Lindelof and Maguire will eventually have to be replaced. There's no need for a witch-hunt. Our worst defender at Villa Park on Sunday was our best player in the season thus far. It was his brain fart that forced Shaw to concede a foul in a dangerous area that led to AV's second goal. It was also his hospital pass that forced Lindelof into a difficult situation in the first place for AV's third goal. Should we crucify him, too?
Even the best defence in the world would struggle to maintain a high line by enforcing a proactive game, week in and week out, for a team that struggles to score more than a goal per game.