I must admit, the notion of being "in" a party in a way an employer can easily check, or party affiliation that is legally registered, is outside my experience. By affiliation I meant only the party a person tells other people they support, in a non-binding social sense. I'm not in the USA.
I agree, where affiliation with a party has greater meaning and consequences, and is practically required for access to ordinary local services, the secret ballot is even more important.
That neighbourhood is a great example.
I'm disappointed, really, that in 21st century USA those people are still disenfranchised by local politics from voting in the primary of the party they actually support. But presumably there are good reasons for legal registration.
You write: > If people choose to announce their party affiliation, that's something else.
In PA (as in most states) one's party affiliation is public by law. In PA it's important because one can only vote in the primary for the party one is registered as a member of. (Voters who do not register an affiliation or are affiliated with a third party simply aren't allowed to vote during the primary.) So it's not really a case of "choosing" to announce their affiliation.
Also, I know multiple individuals in my neighborhood who have confided in me that they registered as members of one party but preferred to vote for the other party. Why? Because (at least historically) our county has a long history of being run by a single party and (to quote my neighbor), "If you are a member of the wrong party your trash won't get picked up."
The secret ballot really DOES prevent certain abuses.