Because of quantum computers threat to bitcoin security.
CNBC's TV host known for his impulsiveness?

TV presenters don't have opinions of their own; they merely voice what they are told to say (by public relations specialists

). Furthermore, he is not a technical expert, so his opinion on the threat posed by quantum computers would not carry any authority.
The article says nothing about what guided Jim Cramer in making his decision. Therefore, these are merely your speculations.
By the way, the article describes the inverse Jim Cramer effect. You should read up on that.
But many people are buying the dip instead.
That is exactly the right thing to do. Especially when someone like Jim Cramer is urgently offloading that asset.

I think he makes a wrong decision. But it is his bitcoin, he can do whatever he likes to it.
Far from it. His decision is the right one, because one of us might be able to buy his bitcoin.

Rejoice in the new opportunities.
I did not know when he bought bitcoin, why publicly announced that he is selling.
Ask his editor (or the channel's management) about that.

He is just a hired employee doing what hes told. Do you really want to put stock in his words and actions?
Bitcoin all time high in few year to come.
Well, of course. After the halving. Dont need to be a visionary here, as it has become a pattern.