Hey, welcome to TBN and congrats on the new tractor.
I can't answer the question of why. But I can tell you that if tym/rk decided not to match a backhoe to that platform, they certainly would not cover any damage to your tractor caused by a backhoe.
Do you have any hydraulic remotes in the rear to power a backhoe? If not, that's the first hurdle. These backhoes run off tractor hydraulics not directly from the 540rpm pto.
I strongly recommend that you do not try to use any backhoe made for a 3pt hitch mount that does not have a subframe. Do some reading on those things if unfamiliar. You will see quickly that you can literally break your tractor in half without a subframe.
A new bh that size is $4-5k+, you could rent a backhoe or mini excavator for a while for that $.
Just food for thought.