Hulu doesn't explain their rationale for this policy, but I've seen it discussed a lot in the Hulu community (see here, for example).
Though this won't help with the problem of the HughesNet IP changes and Hulu having a fit about it, if you use Hulu a lot you may want to look into PlayOn Cloud. Though it's sort of a convoluted way of watching what you want, it may help alleviate that problem, as PlayOn Cloud may always use the same IP address when it's streaming your chosen items to their "cloud based DVR". It's just an idea.
Some of us use PlayOn Cloud for the purpose of avoiding buffering and being able to more easily use the Bonus Zone data for our streaming, but it may help to avert the IP problem, as well. Hulu is one of the providers their service works with, and I've not seen anything mentioned about Hulu and IP addresses, so this may very well be the case.
You'd have to have a way of being able to play the files (mp4) on your TV, though. There are various ways, and if it's a Smart TV it may very well have a USB port with which you can play the files from a flash drive.
Again, it's just an idea.