Why should a person being paid close to 5m per year to do a job be given a free ride to do all the basic things so badly that that article rightly points out? If I went to the theatre to see a play and one of the main actors couldn't act, couldn't remember his lines and didn't always stand in the right places, he wouldn't get "let off" because he's at least out there moving about, it would ruin the whole play, be rightly criticised by paying customers, and he wouldn't be getting 5m to do it.
I don't think he does perform the function he's being asked to perform well, that's not all his fault, he shouldn't be asked to perform it IMO, but his deficiencies are one of the reasons we look so awful a lot of the time he's playing, it also effects this around him and the team dynamic - if people are bamboozled into thinking he's had a good game just because he charges up the pitch and whacks the ball out the stadium twice a game more fool them. He doesn't close down well, he doesn't read the game intelligently enough to do it, he gives the ball away stupidly - as he did against West Ham, in exactly the same position as Trippier did against Wolves, which resulted in an even more dangerous situation (that brought an outstanding save out of Lloris), but we slaughter Trippier and make excuses for Sissoko (or most didn't even mention it)?
Dembele's lack of incisive, creative end product has always been levelled at him, but the reason it gets partially forgiven is not because he's more aesthetically pleasing but because, when he was fit and on form, he did do other things well. His technique is extremely good, his positional sense is good, he rarely gives the ball away, he isn't rattled into miss-controlling the ball, he's tenacious, used to press and win the ball back well.
Whereas Sissoko does nothing to a high standard, in his prime Dembele did plenty of things to a high standard, his only real weaknesses was dwelling on the ball too long and a lack of passing incision.
As much as I'm not Dembele's number one fan, there's a shitload of reasons why he gets less criticism than Sissoko.