Does a high school expulsion affect admissions into university as a community college transfer student?

Yes and No,

Explanation: If one was to be convicted of a felony as a cause of that expulsion then yes it can heavily affect which colleges you can get into because in the eyes of the college admitting you is the same as saying "we have low standards we admit felons" this is bad for colleges because in the end of the day all they want is money running a college is almost the same as running a business so things like hiring bad people will lower your reputation it’s common sense. But if you aren’t convicted of anything and you are expelled well all you really need to do is change, repent, and If your college record is clean and your recommendations are positive, then most admission officials will be willing to give you another chance.