Personal Attacks & Hostility
‘Nobody trashes a name like someone afraid they’ll know the truth.’
The term AD HOMINEM (wiki link) seems appropriate to mention first off, 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.
Unfortunately we've undoubtedly observed situtions where civil discussions and debates deteriorate to a level 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. If someone finds themself partaking or otherwise associating with those who participate in such, it's strongly advised to reassess one's ethics. Simply put, if people are engaging with intent to cause harm - a reasonable person would hopefully realize that's not the best course to take.
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:
See also reactions to deception being caught.