Let me offer a counterpoint. I dealt with a similar situation with one of my clients a few years ago. A pornstar had followed their account (a DoD account dealing with wounded warriors) and they were worried, as you are, about the potential association with their government account. Unfortunately, as I pointed out to them, that pornstar is a person too. A U.S. citizen who may have a brother, dad, sister, etc. in the military who may be truly interested in learning more about the DoD. True, she may have just been a spammer, but what if they weren’t? What if she was truly interested in following that account because of the information they were sharing? Isn’t the government supposed to be serving all of its citizens? Is there a reason to discriminate against her just because I may disagree with her occupation?
I’m not saying this is the situation you’re dealing with and most often, it IS is just a spambot that you can block, but this is definitely something you (and all of government) should be aware of before blocking someone.