Previous cycles, the market takes Bitcoin about 9 months or 1 year after its halving to jump to a Euphoria phase.
The problem is that most people don't understand this. Most are experiencing a halving for the first time and they have refused to study and see how bitcoin performed in other halving. The halving was sold to them as a time when the price rises and gets to a new ATH, they were never told how long that might take to happen. Many people believed it would be immediately after the halving. Another thing that fueled this belief was how Bitcoin performed a few weeks before the halving. We saw bitcoin go from around 50k to 70k in days if I'm not mistaken, so they believed the halving would be like that too.
I've always advised people to take a look at bitcoin price history over the years, see how bitcoin reacted to various events and you'll have an idea of how bitcoin price would react now. It may not be spot-on accurate, but like I said, it will give you an idea.
Not sure how people in masses can buy the idea of bullrun immediately after halving without looking at historical data because it's quite evident that usually it takes around a year post halving for bull run and people jumped in assuming bull run will start immediately after halving and getting panicked for minor fluctuations.