"-ism"" vs "-ity" suffixes?

[cuberdrift]

Greetings, all!

Okay. So can someone help me explain why the suffix "-ism" seems to be added to a concept that seems to be either "bad" or "controversial"?

By contrast, "-ity" seems to be added to a concept that is very widely accepted.

There is Christianity, but not Catholicity. Also not Hinduity, Judaity, etc. There is Democracy, but not Capitalism (controversial), Socialism (also controversial) or Communism (which seems to be outright "evil" in the eyes of most First World nations).

"Pianism" is also rather controversial, which is sometimes used in contrast to the more respected "musicality" (I don't hear the word "musicalism"). We use "virtuosity" because the sound of "virtuosism" would suck, lol.

There's also "authenticity" and not "authenticism" (which would sound perfectly well), "originality" and not "originalism".

Then there's "equality" but not "equalism", "unity" and not "unism".

What seems to be the trend is that the suffix "-ism" is used on rather "narrow" ways of thinking, while "-ity" seems to be used for more generally accepted ideas.

What do you think?

Also, here's an article I found that helps delve into this dichotomy.

Regards,
cuberdrift