That particular comic clearly isn't intended to be humorous. In fact it's quite humorless. Or are you saying the factual inaccuracies are some kind of ironic joke that Alex Knapp and I both missed?
I'm saying you shouldn't take everything you read at face value.
Other commenters talk about Edison is idolized throughout education and glossing over his imperfections.
The Oatmeal is providing an alternate viewpoint that takes some things to the extreme - but proves a point - Tesla was overlooked both in his time and in the education system.
Also, why you might not have found it at funny as his "reasons your cat is plotting to kill you" comic, if you could honestly read the comic and not laugh a couple times at least I'd be surprised.
I think its a bit dangerous because in general people read these and believe them to be true. People are already misinformed about the fact that Tesla created AC power and the comic only further promotes this misconception.
And really the part about Edison electrocuting animals is horrifying enough on its on merits, but to aggravate that by including that he paid little kids to steal pets so he could do it? What about the part where Oatmeal basically said Edison purposely experimented on humans with radiation and killed his assistant and amputated his arms? I am sure Edison was no saint but the author makes him out to be a monster which I think is irresponsible of the author of The Oatmeal to claim without never bothering to research. It seems as though the author just met someone who was a fervent Tesla supporter and took him at his word.
I don't think OP was "attacking" the author. Seemed like a reasonable critique.