I hate (real definition) the expression "hater" (modern excepted definition)
This is what you get when you google the word "hater." The first definition is what it means, the second widely excepted informal definition is stupid. People should be able to argue, contradict, point out logical flaws in, disagree with, or just show a general level of opposition to something without any form of the word "hate" being part of the equation.
Just because someone thinks whatever your thing is is slightly less than perfect does not mean he/she "hates" it. Can't we get a less extreme word to signify this? Cynic, doubter, skeptic, etc. They all work just fine. The world isn't black and what, we're allowed to still describe things from a middle ground.