I'm sorry you're having to go through this. It is very unusual, unwise, and potentially illegal for a supervisor to tell an employee to "pull back" and EEO complaint. On the other hand, the test for a "hostile work place" is much more complicated than whether one person made one discriminatory or race-based comment, or even multiple times. You need to talk through the details with an employment lawyer. There are many talented employment attorneys in Spokane. If you are interested in a referral send me an email and I will give you two names of lawyers who do this work.
I only practice in Washington State and may not practice in your area. This answer is a brief hopefully helpful tip to you which is correct to the best of my knowledge and is meant as a starting point for you to conduct further investigation. However, it is made without knowing the factual details of your case or doing any legal research and so may be in error as to either the facts or law. I am not your attorney and I am not giving a legal opinion by this answer.