The guy who owns the company knows what it means for the long term stock price: a plummet. He knows that’ll come eventually if these changes go through.
Investors may react positively to the news, but when they see the damage it actually does, they’ll pull out too.
The guy running the company has shares that are valued way higher than when he earned them, he is sitting so high right now it’s far worth selling here instead of gambling on the response to the news. It’s just simple “quit while you’re ahead”.