> not everyone harbors racist, sexist, or otherwise wholly objectionable thoughts in the recesses of their mind and certainly not everyone speaks such things publicly.

I'll agree that "not everyone speaks such things publicly." The issue here is that jokes that are funny or at least "okay" in one context are incredibly offensive out of that context, and social media makes it easy for jokes to be taken out of context.

But everyone, everyone has something in their mind that someone else finds objectionable. This is human nature. Even if those thoughts are not voiced or acted on, they are still there. The internet is so large with so many different views that inevitably someone will offend someone else without meaning to; even views that one person does not consider "sexist" could be "sexist" to someone else.