Yet the farmers are happy to see the stock in water
Don't be ridiculous, of course they're not
happy to see their livestock in these conditions.
It wouldn't be quite so bad if the farmers used hay tumblers & raised troughs to put in some dry fodder or feed for the sheep.
They may be constrained as to how they can feed the stock, very often environmental schemes prohibit any feeding and certainly the use of feeders and troughs.
Plus, unless you can provide the correct amount of space for each animal, the use of feeders and /or troughs can be very unpleasant for the livestock, some may even get trampled and/or suffocated. It's generally better with larger numbers to spread hay out along the ground, and if feeding hard feed, use pellets that can withstand being on wet ground for a few minutes.
Even if you have the space for feeders / troughs, they can cause their own problems, such as poaching of the ground and the resultant foot problems, not to mention the length of time it can take for the ground to recover.
Please do not assume that because you see farmed animals being treated differently to how you would treat your small number of animals, that the farmer is doing anything other than the best that can be done for those animals in those conditions.