He can't throw them under the bus publicly. He'll lose the player, he'll lose the crowd and he'll lose the rest of the squad who'll be asking "will it be me next". That style of management doesnt work. It's just gratifying for a short time. He can have a go in private though and I expect that's what he's doing.
You bring Mourinho in, you do it to tighten your defence and win games. He's not doing it. Losing to Leipzig, Chelsea and Wolves is not acceptable. Not by a long, long way. And I don't buy the "individual mistakes" as the sole reason. Sure they don't help but well organised teams can deal with mistakes and cover them. We did it under Poch when we were solid.
Jose obviously deserves more time and needs to get his own players in. End of next season at least. But so far, he's been little better than a shattered Pochettino.