Earlier quoted context omitted.
Sexual harassment and retaliation against employees for reporting it is not "just being jerks". It is illegal.
No it is not. The word "illegal" gets thrown around way too much; it has a very specific definition in law, and nothing you described is illegal.
http://www.sgrlaw.com/ttl-articles/826/
Words are defined by how people use them, and this fits the common usage of the word illegal.
Nobody cares what pedantic definition a lawyer would use to describe this, because nobody made lawyers the language police.