Probably because people have been encouraged to think of coworkers as friends or family.
My personal suspicion is simply the rise of social media enables mob like behavior over due process and rule of law.
And, I'd bet some of that encouragement happens because work-life balance is non-existent in many places and/or many people in tech simply don't have a deep social network outside of work because they tend to be younger/unmarried/relocated, etc.