I was curious, cuz I wasn’t sure either. Wikipedia has a summary:

It won the Hugo Award for Best Novel in 1960,[3] and was praised by reviewers for its scenes of training and combat and its visualization of a future military.[11][12] It also became enormously controversial because of the political views it seemed to support. Reviewers were strongly critical of the book’s intentional glorification of the military,[13][14] an aspect described as propaganda and likened to recruitment.[15] The novel’s militarism, and the fact that government service – most often military service – was a prerequisite to the right to vote in the novel’s fictional society, led to it being frequently described as fascist.[14][16][17] Others disagree, arguing that Heinlein was only exploring the idea of limiting the right to vote to a certain group of people.

Lol And then for the 1997(!!) movie it says:

The film was directed by Paul Verhoeven (who found the book too boring to finish)

It had the stated intention of treating its material in an ironic or sarcastic manner, to undermine the political ideology of the novel.