I'll never quite understand it fully either. Certain players who have made some big mistakes only seem to get remembered for said mistakes, even when some of the points brought up have a reason behind them.
Shite against Chelsea? I think walking with a broken toe is hard enough.
Sent off against Palace? Took one for the team if anything.
The sending off against City was of course stupid, but that's so long ago now as well and in practically every other game he was good.
Every excuse for Smalling playing well can be countered by excuses for Jones & Rojo playing well. Carrick getting into the starting 11, the 433 and pretty much the entire team just (finally) more consistent in terms of playing well and limiting changes.
That's the thing, this season Smalling has only played while the entire team was still finding the correct formation, tactic and rhythm. So most of Smalling's appearances have come while we haven't played well.
Therefore, to the people who don't like him, or the ones who prefer Jones, Rojo or Bailly - that somehow means Smalling is our worst CB.
Compare that with Jones & Rojo who have played every single match with a settled midfield including Carrick in front of them, (a luxury Smalling and Bailly haven't had) Ibra in fine form, Mkhi returned to the side, Martial finding form, Rooney & Fellaini not being first teamers etc.
That's not to say that Jones and Rojo haven't played well because they have, I just don't buy the argument that they're doing what Smalling can't do.
All 4 of our defenders have a similar level of ability in my opinion, and different strengths and weaknesses.
There's no reason to break up the Jones and Rojo partnership, but don't try and justify their partnership as a reason that Smalling is shite.