A travel trailer can be as safe to tow as a 5th wheel, but most are not. I blame lazy, cheap, sorry ass dealers who do not set the trailer up with the correct hitch.
Most throw on the cheapest hitch they can. Some not even weight distributing. Then they add a cheap ass friction sway control device that is almost useless.
With a Reese Dual Cam or Equlizer Hitch, travel trailer can be safe. Pull-Rite or Hensley Hitches are as safe as 5th Wheels. However, the first 2 are $1000-1200 and the last 2 are $2000-2500. Dealer put the cheapest crap on they can and people who don't know better think tat is as good as it gets, or that all Travel Trailers tow badly.
I have a 35 foot Travel Trailer with a Reese Dual Cam and towing is a pleasure. It is setup right. 5th Wheeler require little setup to tow right, but it can be done with a travel trailer.