I'm not racist, I'm just stupid

So the Boston Herald ran this really lame cartoon recently. 

I mean, seriously, if you're going to be offensive, you could at least be funny about it.

Here's why some consider this offensive. For more than a century, the offensive image of a stereotypical black person or child with a big hunk of watermelon was ubiquitous. It was a degrading reminder for African Americans of their sub-human status in white society. 
Following Obama's election, the watermelon cartoon enjoyed a renaissance in less mainstream publications, only with our president as the starring player. You can see several hundred if you care to do a Google image search for "Obama and watermelon" (but I wouldn't advise it if you want to retain any faith in humanity). 
So the cartoonist at the Boston Herald claims he didn't mean anything about it, and the editorial staff plead naivete. And maybe it's my own naivete, but I actually believe them. 
But it makes me wonder... when it comes to journalism, does ignorance absolve idiocy? I mean, journalists are supposed to help people be less ignorant; yet nobody employed at the Boston Herald was familiar enough with the whole watermelon thing to have it ring alarm bells and change the toothpaste flavor (or replace the cartoon with one that was actually remotely funny)?
It reminds me of a decidedly more grave case where journalists claimed ignorance, this one in my hometown. Last year, a trans woman named Cemia Dove was found murdered. Newspaper coverage was shameful. The Plain Dealer ran the story of her death under a headline about an "Oddly Dressed Man" found murdered. The story reported that she was wearing three bras, no pants, and a Betty Boop tank top before it even mentioned her legal name. Her chosen identity, which they could easily have learned, wasn't even mentioned. The pronoun he was used throughout the story.
Once they learned Cemia's identity (and had already been contacted by folks from the trans community about the language in the first story), another story was run, again under a headline calling her a man, this one detailing her history of run ins with the local transit authority to whom, we learn, she had "lied" about her gender and identity. Later, the headline was changed to use the gender neutral "Clevelander," but the content of the story was unchanged.
All right, well, most people outside the community don't know the proper language to use (although people outside the community probably should know that stories about someone's grizzly death probably shouldn't start with fashion commentary, and that a five-minute public records search doesn't qualify as journalism). That's why the Associated Press style guide has clear standards to use when covering stories about trans folk.
The author of the story was publicly indignant that they'd been criticized, claiming that it was perfectly reasonable to not know about these standards. How did no one say "I have not encountered a news story about a transgender person; perhaps I should bother to do a damn Google search on the proper vocabulary to use"?
The folks at the Plain Dealer and the folks at the Boston Herald are essentially seeking absolution by saying "I shouldn't be blamed here; it's not my fault I don't know how to do my job."
Dude, you screw up, you own up. If the Herald had said "gee, that was a really big mistake we made and we're sorry," that'd be enough for me. But instead we get "I'm sorry, but I shouldn't have to be sorry." If the Plain Dealer had apologized and atoned by speaking with the members of the trans community who reached out to them, maybe learned a bit about the alarming numbers of trans people who are violently attacked or outright murdered, it would have turned the situation around. Instead they ran an editorial by another reporter defending the first reporter's ignorance.
And they wonder why my generation gets its news from The Daily Show.