The truth is that Marijuana is not a single drug. It is several different strains and each has its potency and its CBD vs THC ratios.
On top of that, people can react differently to each of the strains of Cannabis.
Another determining factor is the age at which a person starts smoking. If started before 16 years old the damage can be much greater than the ones that started in adulthood.
To answer your question, why some people hate it some much:
1- Not the right type of person for weed
2- Only tried the wrong strains for him/ her
3- Have friends who are not suited for cannabis that smoke and give negative impression
4- Never tried because they are/were misinformed and programmed
5- Hypocrites who smoke every day and pretend that they hate it (I know so many of those)
6- People that like to constantly be in control
I am sure I missed a few others
