I think if he's playing well he should be.
Do I think Sissoko is a better footballer than them? No. He's obviously the weakest of the four ability wise. But statistically (though stats aren't everything), he's been better then all of our other central midfield choices. He wasn't good today and I've already said he was poor but the backlash he gets after such a performance is just ridiculous. He didn't cost us a goal, completed 86% of his passes (Which was more than Alli, Eriksen, Kane, Davies, Aurier and the same amount as Vertonghen), yet people will scrutinise him for one moment in the first half where he misplaced a pass to Aurier on the wing.