People who want bitcoin crash are those who want more profit, they can buy bitcoins at a low price and when bitcoin increases they will sell it.
This is one of the view market participants that's right. They may see want the price to decline because they are short, or they are sitting on a pile of cash, but can not short trade and want to buy or accumulate more BTC. Either to hold it as long term investment, because they believe in it, or they just see it as another vehicle to make more fiat, USD, EUR etc. with it.
Another reason why some people want to see Bitcoin to crash is, because they hate it with a passion. These so called nocoiners, are spitting on Bitcoin since it caught their eyes several years ago! Take a guy like Nouriel Roubini for instance! He is hating against Bitcoin for more than 5 years now! That guy could be rich already! But no, he is a typical blinded keynesain who just doesn't get it. And the more Bitcoin rose in price over the years, the more he hates it, probably himself as well, because of having missed so many opportunities to have been set for life.