This is a topic I've given some thought about, use to think one way, but now I see it the complete opposite.
a "micro-aggression" is the idea that your actions and ideas affect others in a negative way and that you should therefore tread carefully with jokes and words to make sure you are not spreading things such as homophobia ("fag" "gay"), or racism ("nigger" "chink" "spic"). Essentially, if you say any of these things or imply them even jokingly, there's a chance someone may misunderstand your joke and take it seriously. Or may even understand it's a joke, but use that as a starting point for their own prejudices.
The problem with this idea is that it is based in the thinking that we can understand how each person may react to anything we say. If that were the case, we should be wording everything we say more carefully than before. We should also do away with multiple languages, and have a universal language to make communication easier. Wouldn't this be the answer we should be trending towards, if micro-aggression are not only real, but something we should be weighing heavily when considering the words we speak?
My answer is that micro-aggressions should never be considered when speaking. I do not mean to suggest that racism and homophobia are good, and in fact, I am strongly against both. That being said, it's hard for me to accept the idea that people do not have a choice when it comes to accepting influences or information. If person A hears person B say "fuck", and is inclined to say the words because of that, you still have to consider the mindset of person A before they've decided to say "fuck" due to person B saying it. They're attempting to suggest that there is no reason for saying it, or they shouldn't have thought of a better reason other than "person B is my influence, therefore I should say it."
We can't control how people think, but because of that, we cannot determine the consequences of any action done against them because those consequences do not exist until it happens. I do not suggest that people continue to be racist, but to consider your argument when you are attempting to tell someone that their language is an overwhelmingly direct influence on people. People have free will, and are influenced by all sorts of things that make up the equation that is themselves - To consider one person an overwhelming majority should bring up the question of why someone would allow themselves to be so easily swayed by the actions of a person who is not themselves? The person being influenced has free will - why are we not blaming them for not thinking in more than one way?
I do not advocate racist or homophobic speech, but I do think we need to stand back and consider other options when arguing against spoken word. It is no better than trying to argue with an internet troll for they already have an objective in mind and likely do not care whether or not they have influence over another person. If you're going to contest such language, dive into the philosophical argument of prejudice, and it's effect on people. If they refuse, then you cannot change them, and an argument consisting of either philosophical or etymological foundations will have no use anyway.