Good thing. We don't need those (ugly power eating useless purpose) big buildings in our garden.
If it were datacenters to cure cancer or something else meaningful then ok. But it's Facebook.
Compare the DC to a landfill. Do you want one in "your garden"? Probably not, but it's not like you are going to convert to zero waste and render the project irrelevant.
Hey hey, don't give them ideas. We don't want them here.
Plus, given current European energy struggles, when Germany considers rationing power delivery, deploying Facebook space heaters sucking 200MW is not only irresponsible, but should be criminal.
While I see your point in general, also because servers are not typically put in oil or anything so this would be hot air (much less dense than water), I wonder if it's as simple as that. It's not like the Netherlands has spots where you are further than a handful of kilometers from the nearest buildings and, often, towns.
On top of that, the farmland isn't necessarily even growing food. They may be growing, say, tulips.