'Stranger Things' Brett Gelman Says U.S. Healthcare Sucks, But Not a Reason to Kill

"Stranger Things" star Brett Gelman is speaking out after the arrest of Luigi Mangione -- the suspect charged in the murder of a healthcare executive in New York -- saying while the U.S. healthcare system is broken, that's no excuse to commit murder.

We caught up with the actor at LAX Tuesday ... Gelman tells TMZ he understands the frustration with healthcare, but made it clear that being fed up with the system doesn’t give you the right to go out and kill someone.

Check out the video ... because Brett dishes more thoughts on the fatal shooting of UnitedHealthcare CEO Brian Thompson ... telling us the way whoever did the crime should’ve made a point about the healthcare system if he really wanted.

As for the chaos online around Mangione, Brett says it’s upsetting that a space meant to connect and educate has become a breeding ground for conspiracy theories, and disconnects people from what's really happening

No matter the POV on Luigi, one thing's for sure -- he’s got a long legal road ahead after his Pennsylvania arrest. He’s already been denied bail and is fighting extradition to New York.