What reason or law makes this illegal or legal?

The answer is legal.

Explanation:

peacefully protesting something at work would be legal.

i think it can have both positive and negative effects on businesses.

for example:

lets say you own a small business and taxes go up 4% that means it is going to cost your business more money to buy product to sell. but at the same time you make more money from the tax rise.

that is my theory.

"quid pro quo" harassment takes place when a supervisor requires sex, sexual favors, or sexual contact from an employee/job candidate as a condition of their employment. only supervisors who have the authority to make tangible employment actions (i.e. hire, fire, promote, can commit "quid pro quo" harassment.