Wedding Contracts - Cancellation without Cause

That sounds like a red flag to me. I'd either ask for that clause to be removed from the contract before signing, or find a different venue. I'd be nervous about them cancelling close to the wedding, leaving you without a venue and without your deposit to put towards a new venue.

No, definitely not normal. I second everything Lisa suggested.

That clause might be to cover something like covid shutdowns or a natural disaster that is not your fault nor their fault. But they should either be more specific in the wording or omit it. You can negotiate a change of that clause. It would obviously be permitting them to keep your money if they had someone else willing to pay more for the venue. But really, if someone else uses the venue, you again should get your deposit back