It's got nothing to do with agreeing that Ramos isn't defending well - it's highlighting the very valid point that defending your penalty area and booting the ball into the stands whenever it comes near you is far, far easier than playing 40 yards from your own goal with full backs pressing high up the pitch leaving space both in behind and down the flanks.
Put Ramos at CB in one of those teams and ask him to defend the penalty area, he would look absolutely God-like. Put one of those CBs in Madrid's team, ask them to play a high line and press the ball in between the lines AND be aware of the space in the channel...they would look like a Sunday League player
Also, in the video you have posted, clearly it's a tactic worked out pre-game. They look to have a back five with Ramos being asked to step into the midfield to close down Busquets when Barcelona look to work the ball forward. On both occasions, it looks to me like the other CB left too much space between themselves and the full back, the first goal in particular that gap is massive!
On a side note, and for all those saying Van Dijk is overrated, why do we think Liverpool have improved so substantially for the addition of one player? The answer is, he allows them to play 20 yards higher! This helps the midfield enormously as it gives them less space to have to close down and recover the ball and helps them play closer to the front players.
This is also the reason it is SO difficult for the modern top teams to find the right defenders. It is so rare that you find a big, physically strong CB with pace, with a football brain and who is good on the ball.