Since some people are quick to adopt what other people say without trying to find out reasons of their own, the hate speech may make some people never know what bitcoins really are. But the people that hate bitcoins are helping bitcoin in a way because anytime they express their hatred for bitcoins, people will always wonder why they hate the thing called bitcoin so much. They may indirectly be helping to tell people about bitcoins and raise the interest of people to want to know what bitcoins are.
I think that's a problem that can't be solved easily and in a large scale, people being gullible and being easily swayed by an audacious speeches and letters are a problem which could've be solved by proper parenting, critical thinking should start as soon as possible for an individual, although critical thinking skill can still be learned as an adult you will probably meet some resistance because adults have an established beliefs and habits which is going to be difficult to break especially those with bad but feels good vibe habits and beliefs. The only thing that we can do against hate speech is to try to talk to them in a respectful manner, anger is easily diffused by calmness so a moderation in tone or no sarcasm in your speech or letters would be a good way to have a discussion with people that spout hate speech, most of them just wants to be heard anyways.