It is definitely wrong to lie about serving in the Marines. These men train hard and fight for our freedom, and it's terrible that someone would pretend they served without putting in the hard work of actually serving. I think it's wrong to lie about any job, but it's especially bad to lie about serving in the military.
Lying about being in the Marines or any other branch of the armed forces for purposes of deception is wrong. The U.S. military does an important job for all citizens, and to lie about military service is doing a disservice to all American taxpayers. Unfortunately, this type of deceptions is becoming increasingly common.
In my opinion, it is always wrong to lie (unless your grandmother bought you a horrid gift and you pretended to like it). But seriously, untruthfully stating that you served our country is lower than low. Not only are you lying, you are taking credit for what the brave men and women who truly have served our country accomplished.
You shouldn't lie about serving in the military. It's very disrespectful to the thousands of men and women who have died for this country. If you're lying in order to get free benefits and services, shame on you. That takes resources away from people who rightly deserve those services and who agreed to defend this country with their lives.