People think this because its exactly what happened so far. I dont think its naive to expect history to repeat itself, r0ach.
It's inevitable that a Bitcoin halving will be a buy the rumor sell the news event like this Litecoin halving:

hahahahahaha
That is what a lot of peeps said around bitcoin's second halving that occurred in mid-2016.. it was quite comical to then witness how the reduction of new bitcoin supply (in 2016 and thereafter) seemed to have ongoing upwards price pressures on BTC that became even more concrete when the reality was experienced...... which seemed to become more and more stronger after the halving was realized in a concrete physical way with not as many new coins on a daily basis.... etc etc etc (which added up with more and more passage of time).
Who gives any shits about what happens with litecoin?.... litecoin is not bitcoin and accordingly is not the dog, at best litecoin is the tail...., even if it's halvening comes more than 9 months prior to king-daddy bitcoin's.