This isn’t really oniony… Most popular dictionaries are descriptive rather than prescriptive, meaning they document the way language is actually being used, rather than dictating how it should be used. All words or phrases that gain relatively widespread adoption end up in the dictionary, along with tracking the evolution of words as they gain new meanings.

I know what one of the three words in the title actually mean. If you want to know what a word means, you consult s dictionary. If people are actually using these words, it kind of makes sense to add their definitions.

Not sure this is oniony? Delulu was popularised by our PM and both tradwife and broligarchy have definitely made it into the political and social commentary lexicon.