Explanation: "We should bring back the guillotine" or similar is a common internet quip in response to billionaires doing billionaire things, when in reality the guillotine was invented to provide equal and humane deaths to people of all classes, and from there it was always a tool of the state rather than the people. Not the best euphemism for "we should depose the bourgeoisie." In fact plenty of Revolutionary justice folks were themselves offed by the guillotine during the Terror.
The most radical proponents of the Terror were not the wealthy bourgeoisie, though, but the urban proletariat of the sans-cullotes, and while the Terror was an authoritarian government, it was also an authoritarian government directed largely against foes it considered reactionaries. Not to ignore left-infighting like the guillotining of the Herbertists or the shattering of the titular Enrages (who were, themselves, advocates of the guillotine even towards moderate revolutionaries like the Girondins), but it was not the main thrust of the regime. Under the revolutionary French government, including the period of the Terror, countless men who had considered themselves immune to retribution by a popular government by their association with the established ruling class were given a close-shave with the National Razor, which is what most people are thinking of when they mention Madam Guillotine.
This is not to say "holsum Terror justified 😊" - on the contrary, the Terror was rather counterproductive to its stated goals - but rather that as an expression of the potential for violence against established ruling powers, including deeply entrenched classes like the French aristocracy, it maintains symbolic and factual legitimacy.
As Marx once noted, the revolution of the bourgeoisie is a necessary class struggle that must be won before the revolution of the proletariat. The guillotine was absolutely part of that class struggle. That generally in the modern day people are thinking of moving one step closer to equality than a bourgeois revolution doesn't change that.