I agree with you - but the company lays down the rules not me. There are a couple of us who have refused to charge the $100 but the agency owner can get cranky.
And that's a horrible decision by the company, and honestly I'd never deal with them.
I'm Canadian, and haven't dealt with a Canadian cruise agency since my very first cruise. I advise all Canadians to look for the best deals they can find, and those are sadly normally south of the border.
The good news, they are a phone call, email, or click away.