Yes, he's a liability on both ends of the court. Yes, the team has to know this. Yes, that begs the question of why they've been giving him all these minutes, to the obvious detriment to the team's chemistry. No, I don't think it's likely to change any time soon.
I'm not a fan of force feeding minutes to a guy when it's not needed or merited. The Celtics, however, seem to have liked that approach with Hayward from the start.
Hopefully all this is worth it. In all honesty, without the insertion of Hayward in the rotation, the Celtics would have been right up there competing with the Bucks and Raptors for the #1 seed.
We can't turn back time or wish the Celtics had never signed Hayward, which was probably a mistake from the start. He is a teamplayer, so he has that going for him and he doesn't need to be a prime scorer to be valuable. Let's hope for improvement.
If you have a team with a reasonable shot at a top-4 playoff seed without going all-in on the regular season (which is the case for us - I think we'll end up in the 3rd position), then you have the luxury of working through the regular season and saving your fastball for the playoffs. Celtics coaching and training staff probably think it's best for GH to get game reps often and that is the best thing for his conditioning and head space. And because we don't need to scrape for the playoffs, we can afford to do so even at the detriment to the regular season, potentially.
When the playoffs arrive and if GH is not able to contribute, expect a tighter leash. Until then, let it ride, support him, let him fail and get back up again, let him have successes (30 points games, triple doubles) - let him be a player and they will hopefully reap the benefits end of this year, otherwise next season.