The problem with distasteful actions by ANYONE, is that there are always going to be people on their mental/emotional fringe that will use those distasteful actions to justify their own violence against those people, or support violence in support of those who show violence/ dislike / distasteful imagery toward a different race, or sex, or political identity, or culture, or religion. So, the depiction of violence/ dislike / distasteful imagery on either side of an argument can lead to more violence....which in turn "justifies" revenge or more violence.....and the cycle continues.

This is the same cycle of violence and revenge that happens in street gangs. Perception of a differing group that "disrespects" or "offends", or commits violence against that gang just leads to retaliation, which leads to more retaliation.

Historically comedy has been on the fringe of what is socially acceptable. Language was first to challenge social norms (i.e.: Lenny Bruce) but now, a great many comedians use "rough" language in their acts, and few of their fans object. Those who do object, don't become, or remain fans.

Unfortunately, the "comedic" actions which have been demonstrated recently, in my opinion, were ill advised for a number of reasons.
First: timing. Because of the association of beheading with terrorist groups committing that act against civilians, the act and even the semblance of the act is ill advised, and emotionally trying for many.
Second: Using the image of the President of the United States is also emotionally trying form many.
Third: Even though the comedian apologized afterward, one cannot take back words or images in this time of internet immortality.

We all must try to recognize that there is a "LINE" and that in our responses, in our actions, in our speeches, we do not give those fringe elements reason to carry out their violence.