Donald Trump seems to have quite a bizarre sense of humor. Recently, he's "joked" about suggesting that "Second Amendment people" know how to respond to a Hillary Clinton victory in November and inviting Russia to commit espionage.

Shortly after Trump's controversial remark about the Second Amendment at a Tuesday campaign rally in North Carolina, appellate lawyer and former English Professor Jason P. Steed unleashed a whirlwind of tweets that nail exactly why Trump's jokes are no laughing matter.

Humor isn't random, Steed pointed out. It serves a crucial social function.

In "The Social Function of Humor in Interpersonal Relationships," psychology professor and author Avner Ziv explained that humor is used to forge interpersonal relationships and shapes how we participate in society as a whole.

We use jokes to define who we are, who we relate to, and who we view as outsiders, Steed explained on Twitter.

Racist jokes, for instance, aren't just "bad" if someone they might offend is in the room — they spread the idea that racism is itself acceptable.

In his 2011 book "The Rhetoric of Racist Humour," Simon Weaver, Ph.D., argued that racist jokes reinforce actual racism.

“The research provides an answer to the ‘it’s only a joke’ response by showing that humor, as a form of rhetoric, has characteristics that mean it is highly likely to provoke a response of a serious nature," Weaver explained in a press release.

Jokes don't just tell us who belongs and who doesn't, Steed asserts. They also show what ideas the groups who enjoy them condone and endorse.

When Trump "jokingly" suggests using the Second Amendment to respond to Clinton, he isn't just saying the person it is directed at is unacceptable. He also is condoning the idea that violence is itself acceptable as a response to something or someone you object to.

This is not the first time Trump has "joked" about violence. At a February rally, he said he wanted to punch a protester in the face.

Of course, there are some satirical forms of humor that work differently, and portray extreme offensive or dangerous behavior as a means of social correction.

For instance, after Twitter users observed that Trump often attributes unproven claims using the phrase "many people are saying," some of them used the hashtag #manypeoplearesaying with deliberately absurd examples.

This Twitter user isn't asserting that Donald Trump is actually a secret Muslim. They are making a joke to point out that Trump has used this phrase to suggest that "evidence" exists instead of actually providing it.

But, as Steed remarked, its "pretty clear" that Trump's violent rhetoric isn't a satirical commentary on violence.

Instead, it elevates and normalizes it and acts as a social glue between those who "get it" and those who don't.

When you laugh at Trump's violent suggestions, you are covertly endorsing a society in which violence is normalized. And there's nothing funny about that.

You can read Steed's full series of tweets on his Twitter.