The "local nature" (barely anything left), has already been sacrificed for decades to this. For example, a large drop in insect populations has been recorded, likely because of intensive farming practices. So continuing to do this (apart from EU regulation) does not seem to me like it is very wise. Agriculture is also very dependent on some kind of local nature existing (think pollinators). If you don't care about nature at all, it will be a very dead place soon enough. We are also part of nature, after all.
Note that some of the nature areas are very much man-made. Generally they are the result of either over-farming or over-logging which really reduced the soil quality and gave space for species that can handle poor soil. That is making the impact of nitrous compounds much bigger because it fertilizes the soil which displaces the species used to very poor soil.
As for insect population, that is to do with pesticides, and horticulture. The farming problem causing these protests is nitrous compound emissions caused by keeping livestock. That is a totally different group of farmers.
