What did these people on West Bank do to deserve being arrested and their homes ransacked?

Nothing. However, the ransackers wanted an excuse.

What connection to Hamas or the massacre on Oct 7th does this theatre have?

Both are Palestinian, that's it. It isn't like there is coordination between the two groups, just that they fall under one ethnic group.

What difference is there between defacing the theatre with menorahs and stars of David vs. a crooked swastika?

Really only in context to its use in other cases.