You are likely correct with your observations on that travel agent. Oddly, Carnival is the parent company of HAL, and Princess, Costa, Cunard, Seabourn, etc, etc.
Frankly all cruise lines appeal to certain segments of the market. The industry has grown so large, so many flovors and choices, I think they are all good. If you like that segment..it is the best, if not..maybe your worst. HAL appeals to a traditional, low key cruising enviroment. It is relaxed onboard, gracious service and a low density enviroment. It also, traditionally, caters to a more senior clientel. If that is your expectations...it will be your best. If you expect high energy, neon and chrome, late night energy and young clientel...you may be in for your worst.
Frankly, I cannot understand ANY travel agent criticizing a major cruise brand, especially compared to it's parent company. I would think a wise business would adopt a 'to each his own' attitude and encourage people to enjoy all the aspects of cruising that appeals to them.
I have sailed HAL 3 times this past year; Amsterdam in Alaska, Veendam in the Caribbean, and Prinsendam back to Alaska. I loved them all. Some more than others. But for all the cruises and brands I have tried..HAL appeals to me. It is my best brand.
Enjoy your cruise..enjoy the variety the industry has to offer and remember the critics who only criticize in the negative may be missing out on something.