1) Murderhoboism has nothing to do with the alignment on the character sheet.
2) Alignment as an indication of behavior is very poorly corelated. I find in general that people justify all kinds of terrible behavior anyway.
UPDATE: Reading more of the original post more closely, it says all kinds of things that the data doesn't support. What in the world does "found family storytelling" have to do with anything, and why would a 2.5% uptick in paladins and bards registered in DNDBeyond lead to that conclusion? Not impressed. Made a strange conclusion, and as evidence of it, showed data that had nothing whatsoever to do with the conclusion. A much more compelling conclusion would be that Chris Pine and Sam whatshisface's character from Vox Machina have led to the popularity of the bard, and the mechanical changes to the paladin led to its uptick. How in the world you've concluded that murderhoboism is extinct based on that is... opaque, at best.
That's still just a hypothesis, not proven by data, but it's a much better null hypothesis then the one you've proposed, which is completely unrelated to the data that you've shown. Yours isn't a hypothesis supported by the data, as you claim, it's a non sequitur just so story, and you've thrown unrelated data at it and pretended like it somehow supported the just so story.