I don't think anyone took Jesus to literally mean to maim themselves...Unless you have a point I am not seeing.
1. I absolutely think he meant exactly that. Why? Because the whole point was to bring people to the point of despair where they would say "We can't do it! We need a savior!". That was His mission. Everything He said was for the purpose of getting people to understand the need for a Savior.
"Love your enemies..." - an impossible command. Points to the need for a savior.
"Turn the other cheek" - a near impossible command. Points to the need for a savior.
"Be perfect, just like God." - a clearly impossible command. Points to the need for a savior.
etc
etc
etc
This brings up my second point...
2. I have a pet peeve of churchians using Christianity/God as an excuse for cowardice and other character flaws. Examples:
"I pay my taxes because Jesus said to." - No you don't. You pay your taxes because you're scared you'll get thrown in jail if you don't.
I had another one where this kid broke up with my niece saying "God told me to breakup with you." - No He didn't. He just lacked the courage to tell her he wanted to break up just before their wedding. I don't care if you break up, but don't blame it on God!
Dan Cathy makes a show of polishing the shoes of a black guy to supposedly show a contrite heart. - No. He was just grandstanding and trying to curry favor with a world that hates Christianity. The black guy even caught on saying that Cathy did it for the stock price!
Finally here we have a guy on the Internet saying he would rather lose his freedom (and I guess the freedom of his his family, friends, progeny, and countrymen) than to kill someone attacking him or us. He says he would make this sacrifice out of love for his enemy. But I think that's just more grandstanding.
You can always spot a fake when they make a show of obeying the "easy" commands while ignoring the hard ones.