It's just people try to rise up in arms against everyone who "steals" characters, including OCs and fursonas, and the "stealing" term can mean basically any kind of similarity in their militant senses. No art can be made from nothing, and no art can be taken down without a trace. When someone has so distinctively looking OC/fursona, there's just been a lot of influence and inspiration during the creation process. And, it's not that the person has worked hard enough, probably he just made something he enjoys and is happy enough with. Some people grind their work and they end up with nothing, and some people rock out their imaginations with little to no effort. I know there are common fursona designs that are so common as they cannot literally be "stolen" or misappropriated, such as white dogs (I've seen a lot of them, different breeds etc!) etc. In "feral", realistic looks, it's nearly impossible to rip off someone because naturally animals always look similar despite every specimen being unique enough biologically.
I even have been suspecting that many people will regard using doll makers, avatar makers etc such as one in Animal Jam or other virtual worlds, or Create-a-Sim, as the tools to get inspiration or the complete design of the character, as "stealing" too. In my opinion, it's totally okay and in fact it is a great way to practice being creative.
Most of all this craze against "art theft" comes from the fact that when people can't draw, they commission art, and this requires money. And when someone else uses the commissioned art for any purpose, it is an unwanted situation since the art was supposed to belong only to the one who commissions art. And they preach people to "respect" the artists - however that's no different from plain copyright acknowledgement. But this is not just knowing the exact author, it's also trying to abstain from involving this art in any art activity - including referencing and inspiration, which is inseparable from any art activity and is a part of learning to draw.
Staying on the topic, I would basically "steal" from anyone. However I would rather randomly mix it up and create a derivative, similar character rather than using the original artwork directly.
Now go report me.