I am going to be on the fence here a bit and say I agree that the team is somewhat soft (I would also call it entitled), but not because of the stats that the original poster mentioned. To me that original 'why' of the post isn't correct at all. It actually proves the opposite.
But at the same time you have to admit that just from an eye test, we have a bad game and don't always respond with better effort the next game. A bad call will go against us, and we can't mentally move on fast enough. Tatum, as talented as he is - and yes his ceiling is an MVP, is easily disrupted a bit mentally and will kind of complain too much and have bad body language. It is kind of the softness that comes from immaturity and inexperience, and a bit of entitlement. Both Smart and Jaylen have had similar issues, but to a lesser degree. Even Paul Pierce was like that early in his career.
I think / hope that some of that softness naturally corrects itself. I expect and hope that an early exit this year from the playoffs (which I expect will be our result) will harden our guys a bit. The J's seem to be hard workers and they are getting better, but they are two YOUNG guys who have had a lot of success early, and it probably wouldn't be terrible if they kind of took it on the chin this year a bit to give them a bit of a chip on their shoulder.