It's hard to know what to say to this.
No, you can't reasonably expect everyone out there to both 1. understand chemical formulas and 2. understand their long form names (which is a significantly different case, as people here seem to be forgetting).
In my opinion, you also can't blame a couple of DJ's for making what to many of us is just a dumb joke without first considering what many of us would also call an illogical, ill-informed, totally unfounded backlash. They put together a lot of material very quickly and part of their job is being, to a point, controversial.
That this could be construed, through misunderstanding, as something that could be called a felony and termination-worthy... while you can see it (if not agree with it) in hindsight, to suggest that they should have known better seems a bit out of step with reality.
This could and should have been dealt with by way of a mild reprimand and an on-air explanation and apology. That they were fired and that people are discussing litigation (if not pursuing it, which is not clear from the article) is a severe and dangerous overreaction of the sort that's becoming painfully common everywhere.