I got the same thing when I went to an RV lot.. The guy came out of the office as I was parking my truck (97 F150 at the time). I knew what I wanted and I knew what weights I wanted to stick with.
I told the guy that and he said, "oh heck, your truck can handle more trailer than that". I say, "well, not really and besides I don't want that big of a trailer anyway". I asked to see trailers with a queen bed, full width bath, no bunks, no slides and no more than #5500 GVWR..
He kept taking me to rigs with everything I didn't want... After the second one he tried to steer me to I went to the side where the weight sticker was and looked at the GVWR and would simply say, it's too heavy..
He tried all the tricks in the book. Like saying, "well your family is going to grow, so you need a trailer that will be able to handle that" and he again said "your truck can handle any of these trailers just fine".. I turned and said, "I don't have a growing family, it's just 2 of us and I can't afford those bigger trailers and I don't want to tow that much with my truck". I asked again if they had any trailers like I originally asked about and he said "no, we don't carry anything like that".. I said, "well, you should have said that when I got out of my truck and not wasted your time or mine" I said "thank you, have a nice day" and left.
Never went back to that dealer again. They went out of business a year or so later... ;)
The place I ended up buying from started out with the same speech and I simply said, I'm not interested in those.. I want to look at those ones over there, which was exactly the trailer I wanted... Still have that same trailer to this day and it's been great!
Good luck in your quest.. The best advice I can give is to just have fun with the salesperson if they get pushy or won't listen to what you want and if it comes down to it, simply walk.. :) There are lots of places to buy an RV from, so take advantage of that..
Mitch