I don't think "Bad Habits" is the appropriate term, necessarily.
Playing at lower difficulty levels could lead to you playing less efficiently for a win, since lower levels are more forgiving of experimentation and less efficient play.
I think we should make a distinction between:
Playing styles that are actually bad habits.
And
Playing styles that are considered bad habits because they don't measure up against other strategies more empowered in the game.
Placing cities at bad locations, forgetting to trade luxuries, not building an army, letting barbarians run amok, bad district placements, not prioritizing crucial resources. Those are bad habits and it is true that you can get away with many of them at lower difficulties.
The problem we are highlighting here however, is that integral parts of the game that players enjoy are more and more becoming "bad habits" in the game.
Specifically, Wonders, Religion and basically just not being a Genghis Khan.
Wonders, Religion and building are all crucial elements of the game. The fact that they can be cast aside so easily and without significant consequences speaks volumes about the state of imbalance in the game.
This imbalanced destribution of power to different but sound strategies can only result in overcentralized play styles.
You want to play this way and that, but you can't because they're just not as good as that one boring thing that is just better than anything else. It's just not satisfying to try out other strategies that you know is just not as powerful.
In short, the freedom to play/execute strategies is directly related to the amount of power the devs allocate to different elements that make up the game and in order for freedom to truly exist power must be evenly distributed.
Wonders/Religion/Peaceful Expansion are just very underpowered right now so they are automatically regarded as inefficiencies and "bad habits".