This summary is not the rule. The rule text controls.
When you vote in a secret ballot election, you have the right to keep how you voted private. No one can force you to tell a court, or anyone else in a legal proceeding, who or what you voted for. This protects the privacy of your vote just like it's protected at the ballot box.
There are two situations where this privacy right does not apply. First, if the vote itself was illegal, you cannot use this privilege to hide that fact. Second, if election laws specifically require you to disclose your vote in certain circumstances, those laws override this privilege. Outside of these exceptions, your vote stays private and cannot be forced out of you in court.