Nowadays it seems like NRA and anti-gun proponents inevitably rise up and clash after terrible episodes like Columbine and Sandy Hook (and then sadly dissipate). Did such strong debates happen after RFK, JFK and MLK Jr? Did anything result from it? Or were society's attitudes about guns different back then?
Yes, and it led ultimately to the Gun Control Act of 1968, which (among several other provisions) created categories of "prohibited persons" barred from possessing firearms (a category that includes drug users, illegal aliens, felons, and "mental defectives"), and required the commercial trade in guns to be conducted through federally licensed dealers who were required to complete transactions in person and record the sales.
This second provision is the most directly related to the Kennedy assassination, as it prohibited direct consumer mail-order sales of firearms. The rifle used to murder President Kennedy had been purchased by mail from a magazine ad, and much debate centered on restricting this kind of sale.
President Kennedy was shot in 1963, and the appropriateness of additional legal restrictions on gun possession and transfers was debated through the mid 1960s without any major federal restrictions being passed. The Gun Control Act was ultimately passed in 1968 following the murders of Martin Luther King Jr. and Robert Kennedy earlier that year.