I am having a lot of trouble visualizing Karl Marx's socio-economic class Lumpenproletariat.

Marx gives these examples:

Alongside decayed roués with dubious means of subsistence and of dubious origin, alongside ruined and adventurous offshoots of the bourgeoisie, were vagabonds, discharged soldiers, discharged jailbirds, escaped galley slaves, swindlers, mountebanks, lazzaroni, pickpockets, tricksters, gamblers, maquereaux [pimps], brothel keepers, porters, literati, organ grinders, ragpickers, knife grinders, tinkers, beggars—in short, the whole indefinite, disintegrated mass, thrown hither and thither, which the French call la bohème.

So basically just everyone who is thought poorly of? But why would a brothel keeper not be Bourgeoisie or Petite bourgeoisie? It does not matter if they are extremely successful and control the means of production, as long as their role in society is considered slightly dirty?

Additionally, he states that in addition to being figuratively dirty they are the enemies of the communist revolution since they depend on the bourgeoisie on a day-to-day basis. But how important is this second point? If you generally do well in society, but are dependent on it, are you Lumpenproletariat? Is someone with 100K in student debt Lumpenproletariat, even if society really does not look down on them?

So who are the Lumpenproletariat in the modern world? Presumably the criminals and welfare recipients. But would we include other groups as well?