Hostility
Over the years, there have been incidents in fandom that were undeniably hostile, most commonly taking the form of personal attacks, as well as threats and manipulation.
Personal Attacks
AD HOMINEM (wiki link) is a Latin term referring to attacking the person instead of providing a credible response. This tactic seems to have become more common, especially when used by those seeking to avoid answering for wrongdoing.
‘Nobody trashes a name like someone afraid they’ll know the truth.’
Threats and manipulation
These issues have popped up and while fortunately criminal threats of physical harm are quite rare, we've too often seen lashing out with baseless threats of legal action. Manipulation often takes the form of acting in bad faith to hide or redirect valid criticism away and avoid accountability.
The two most common examples seen are:
1) Efforts to suppress or hide wrongdoing instead of taking appropriate corrective actions.
2) Over-reacting with hilariously illogical/false/bad threats (legal or otherwise).
‘Stop that/do this – or else’ is an interaction that should immediately be addressed and assessed based on (lack of) merit.
Unfortunately we've undoubtedly observed situtions where civil discussions and debates deteriorate to a level of hostility where those who act and believe differently are perceived to be an enemy when at most could be considered opponents. Sadly fandom is not immune to this, an example includes unconscionable online hate campaigns that engage in terrible and even dangerous actions.
There is no excuse for abuse.
Also please take note about a recent (December 2023) Canadian court case made a decision of interest in reaction to hateful personal attacks:
Disappointingly, instead of owning up to unacceptable actions, some organizers and events have employed the above tactics - usually in response to their own wrongdoing. For example, creating social media posts spewing hateful and provably false personal attacks is obviously not an appropriate response to being asked questions regarding financial statements.
An example of a (hilariously bad) legal threat in an attempt to suppress valid discusion and criticism:
A 2015 incident with someone demonstrating zero legal experience (and non-existent legal team) sent a hilariously bad legal threat.
The original comments remained, and this image is still found floating teh intarwebs.
There was no 'client' nor any professional representation with those people, just another manipulative abuser pretending to have a scrap of credibility.