In Halloween (‘78), Loomis spends the entire movie trying to convince everyone that his patient is dangerous to prevent a slaughter. He is finally able to convince the Sheriff of Haddonfield to investigate the Myers house, where he gives the famous speech about the Devils eyes. After this, Brackett says he wants to notify the television and radio networks of The Shape’s presence and Loomis tells him not to, stating that “they’ll see him on every street corner they’ll look for him in every house, just tell your men to keep their mouths shut and their eyes open.” What exactly does that mean? What reason is there to not notify the people of Haddonfield through the news that there’s a maniac on the loose in the town? He’s already been to his house and is currently on the move. If he truly believes Myers is dangerous then there simply is no logic behind this decision. Maybe if the people of Haddonfield were notified, Laurie could’ve connected that to the stalker she’s been seeing all day and been more cautious? 
Well, for reasons like what happened in H4, where Earl and the crew end up killing their own because they are seeing him “everywhere”, causing more unwanted deaths. That’s really what it boils down to.
Imagine if Myers had swapped vehicles and taken the Phelps truck.
To avoid spreading mass panic/hysteria.
Because he didn’t want what’s going to happen in Halloween Kills.
This is true, Michael turning Haddonfield into a Ghost town
pretty good way to put it
He most likely didn’t want a lynch mob to form like in H4, he wanted this handled by officials instead.
Just like what happened in H4. The local lynch mob roaming the streets and end up killing an innocent man. Also to stop as mass panic and people freaking out.