One disturbing aspect of human behaviour is the 'ad hominem' attack in response to a rational and reasonable argument, or an expressed opinion on some matter which is actually separate from the individual, such as a photo. I encounter it myself on this forum, from certain individuals whom I shall not name.
The best explanation I can find for this behaviour is the Freudian and Jungian theory of 'psychological projection'.
Generally, if someone presents an argument or opinion which is disturbing in the mind of a certain individual, such an individual might often try to protect himself from the consequences of serious consideration of the argument or comment, by projecting his own, subconscious, negative qualities onto the person making the reasoned argument.
I always try to avoid such projections, and instead try to address the logic and rationality of the argument or the critique. Of course, I don't claim to be perfect, and sometimes I also fall into the trap of responding to ad hominem attacks in like manner, but very rarely.