If I went the Breeze route I wouldn't be using the lift attached to the back, instead towing with a tow dolly. Weights add up fast and 4500 can quickly be exceeded. The motorcycle is a HD touring coming in at 900 pounds. I am also aware that designers and manufacturers know their product and limitations. The question was centered around why if anyone knew.
To another line, even with a towing weight of 10K which gives a tongue weight of 1K, with a lift of 2-500 pounds and large touring M/C, no motorhome can handle that if you go by the stated tow limits. You would have to have a tow rating of around 15K to meet that.
DR